Weather Forecasting

 
It's Rebecca again, I've been fielding questions on how a weather forecast is made and what it takes to make a forecast. So I thought I would do a few installments on weather forecasting. Now this is not intended to make you a meteorologist. However, it will give you a good idea on what it takes to make the type of forecast you see on WTEN. I will cover how weather models, skew-T/log-P diagrams, severe weather indicies are used to make a forecast. I thought a good place to start would be how you can make your own backyard forecast, just by observing what going on around you.

Not too long ago all the technology we take for granted didn't even exist. Therefore, people had to predict the weather based on observation, patterns, cloud types, folk lore, and even the behavior of animals. These warning signs for bad weather are not fail proof. But, it's much more accurate than you might think. If you're outdoors a lot being able to forecast foul weather with simple observation is a valuable skill. You will be able to make an educated guess on doing things like: hiking, horseback riding, or going for a boat ride. A lot of what I'm going to tell you was taught to me by my grandparents. I will tell you the folk lore, then show the science that backs it up. Also, I will show you common clouds and how they can help you make a short term forecast. I hope you find it interesting.

The Mechanics of Bad Weather

Most of you have heard a cold front or a warm front is moving in. Or, we have high or low pressure dominating overhead. However, how many of you know what they are.

A cold front is the leading edge of a moving mass of air. It is heavier, colder, and drier than the air it is pushing into. Whereas a warm front is the leading edge of a mass of lighter, warmer, and moister air. Cold fronts push underneath warmer air. Which forces the warmer air to lift. This in turn causes it to condense into clouds.

A high-pressure system is generally the result of the dense air of a cold air mass falling toward the earth, whereas a low-pressure system is the result of a warm air mass rising. As the warm air rises, it cools and forms clouds and possibly storms, so low pressure systems are usually associated with rain.

Making a weather prediction by seeing what's going on around you

You can predict short term weather with something as simple as smoke coming out of a  chimney. If the smoke is flowing down or laying close to the ground;  it means it most likely going to rain soon.  This is caused by an approaching cold front or because high humidity is absorbing smoke particles.


At night if it seems there's fewer stars out than normal it might mean a storms is on the way. This is because, when there is a lot of turbulence ( wind shear) in the air it's harder to see the stars.

If you see a rainbow and the wind is coming from the same direction, it means the rain is moving toward you.

Weather folklore and wives tales.

Weather lore has been around since people needed to predict the weather to plan their activities. I'm sure most of you have heard the weather predicting rhyme:  "red sky in the morning, sailor’s warning; red sky at night, sailors delight". There are variations of this rhyme in such places as Shakespeare's  play "Venus and Adonis" and even the Bible.  But, is this true or just a wives tale?  The answer is it's true in the Northern Hemisphere. In order to understand why this is true, we must understand how weather systems move and the colors in the sky. In the northern hemisphere the weather is influenced by the westerly trade winds . Therefore, weather systems normally move from west to east. The colors we see in the sky are a result of how the light rays are being split. The thicker the atmosphere, the more water vapor,  and the higher the amount of other particles in the atmosphere the more the light is scattered. with all of this in mind let's take another look at the poem.
 
Red sky in morning, sailor’s warning.

 A red sunrise reflects the dust particles of a system that has just passed from the west. This indicates that a storm system is most likely moving to the east. the deeper the red color in morning sky the higher the water content in the atmosphere. So, rain is on its way.


Red sky at night, sailors delight.


 When we see a red sky at night, there is a high pressure system with dry and stable air  to our west. The high pressure system is stirring up dust particles in the air. Therefore,  the setting sun is sending its light through a high concentration of dust particles. So, basically good weather will follow.

“Mares’ tails and mackerel scales
Make lofty ships carry low sails.”

Now  what do mares tails and Mackerel Scales have to do with the weather?  Mares tails are cirrus clouds, which are high clouds composed of ice crystals, called this because they often look like flowing tail of a horse. Mackerel scales are actually  altocumulus or cirrocumulus clouds. They often appear to resemble fish scales. They exist lower in the atmosphere than cirrus clouds, and are formed by small convective currents and instability in the atmosphere Cirrus clouds taken by themselves normally indicate  fair weather. However, If they are soon followed by mackerel scale clouds, they could indicate bad weather. Now while these types of clouds don't drop precipitation.  They do, often precede an approaching storm front by 24-48 hours. However, it is  possible that  the bad weather might pass near but not over where you're observing from. I will include pictures of both of these clouds at the end of this post.

“A summer fog for fair,
A winter fog for rain.
A fact most everywhere,
In valley or on plain.”


There a two ways fog form. The first way,  is for the temperature to fall to the dew point, in which the humidity rises to 100 percent. This happens on clear and calm summer nights. A cloudy sky acts like a blanket and holds in the heat of the day, so fog won’t form because the air temperature can't reach the dew point. So a summer fog means clear and calm weather is ahead.


Fog can form if there is warm and moisture air flowing  over a cold surface. This is how most winter fogs form.  In this cast the Warm and moist air is a forerunner of rainy weather.


Here is another one that talks about the same thing, it just talks about dew instead of fog.


“When the dew is on the grass,
Rain will never come to pass.
When grass is dry at morning light,
Look for rain before the night.”



If there is no dew on the grass, it either means the sky is cloudy or there is a strong breeze, both of which may mean rain is on the way.


“Rainbow in the morning, Shepherds take warning.
Rainbow at night, Shepherd’s delight.”


Rainbows always occur in the part of the sky that's opposite the sun. When you see a  rainbow in the morning; it means the light from the rising sun is refracting through the water droplets in a rain cloud to your west. Therefore, a rainbow in the eastern sky would happen in the evening. It would mean the rain has pasted you and is to your east.


 “When leaves turn their back ‘tis a sign it’s going to rain.”


Trees like the oak and maple have leaves that will curl when the humidity is very high; high humidity can  indicate an approaching storm. Also, the way the leaves on a tree grow is determined by the prevailing winds. Storm winds are naturally non-prevailing, blowing the leaves backward from their normal orientation thus showing their backs.



 " The higher the clouds, the better the weather."


When the clouds are high, you have high pressure and dry air overhead.


“Pale moon rains; Red moon blows.
White moon neither rains or snows.”


As I've said in past post, raindrops form around a dust particle or other small object,  the more dust particles there are in the air, the greater the chance that moisture will have something on which to form raindrops. When there are a lot of dust particles in the air, the moon will appear pale or reddish. It looks white when the air is very clear.


“When the wind backs; and the weather glass falls
Prepare yourself for gales and squalls.”


A backing wind is a wind that changes its direction in a counterclockwise manner; for the most part it will start in the west, then change to the southwest, south, and then southeast.  When you have a backing wind it indicates that low pressure is approaching from the southwest.


The Weather glass was an early form of barometer. When the weather glass falls, the atmospheric pressure was lowering, signaling the approach of a storm. 

Pictures of  clouds

Clouds tell us much of what is happening and when. Fluffy cumulous clouds tell us the weather is fine and clear sunny skies usually host those. Dark stratus clouds block the sun and spell rain or snow. Cumulus Congestus clouds also known as towering cumulus form when the atmosphere becomes unstable and there are upward air currents. Cumulus clouds can develop into thunderstorms by evening.


                                                              Low Clouds

Stratus clouds

Stratus is from the Latin for layer or blanket. Stratus clouds form a low layer that can cover the entire sky like a blanket. Rain and drizzle often come from stratus clouds. If they lift quickly in the morning, they often indicate a nice day ahead.

Nimbostratus Clouds

Nimbostratus clouds are dark sheets of clouds which blot out the sun and are often followed by long-lasting precipitation within a few hours.

Stratocumulus Clouds

Stratocumulus clouds are low, rolling mass of thin, lumpy gray to white clouds. They may produce light precipitation but usually dissipate by the end of the day.

 Middle Clouds

Altocumulus Clouds

Altocumulus clouds are larger than cirrocumulus clouds and, they are patterned white to gray clouds that are often rippled or appear in waves. Altocumulus are considered fair weather clouds, they often follow storms.

Altostratus Clouds

Altostratus clouds are formless gray to bluish clouds that form a thin veil over the sun and moon. If the clouds gradually darken and blot out the sun or moon, precipitation will follow.

                                                                   High Clouds

Cirrus clouds 
 

In Latin, the word cirrus means curl. Cirrus clouds are very high in the atmosphere where the air is very cold. These clouds are made of ice crystals. They are usually associated with fair weather, but may sometimes indicate that storms are on their way.

                                                                   Mares Tails

Cirrostratus Clouds

                                                         Above  Mackerel Scales

                                                          Halo around the sun

Halo around the Moon

Cirrostratus clouds are milky, white-veined clouds that produce a halo around the sun or moon. Often called 'bed-sheet' clouds, Halos are another warning sign that bad weather is on the way. A halo around the sun or the moon is caused by light reflecting off ice crystals, generally found in cirrostratus clouds. This  type of cloud can indicate a warm front is coming, and that rain or snow might be expected in 24-48  hours. The brighter the halo, the more likely it will rain.

Cirrocumulus Clouds 

Cirrocumulus clouds appear in layers that look like rippled sand or fish scales. Nicknamed mackerel sky, they are considered an omen of good weather.



Cumulus clouds

I've talked about cumulus clouds before. They are flat-bottomed and have growing, cauliflower-like towers. They often form around midday and precede cumulonimbus clouds.

Cumulonimbus Clouds

Cumulonimbus clouds nicked named thunderheads, are towering storm clouds that can reach as high as 60, 000 feet. As most of us know they bring heavy rain, sleet, hail, thunder, lightning and Even tornadoes.

 

A site on clouds

http://www.weatherscapes.com/album.php?cat=clouds&subcat=cg

Well that's it for part 1. I have always found weather lore interesting. The question of the day is: sometime in the future will the complicated equipment  meteorologists use today ever be considered in the same light?  The folklore I've talked about here is not always accurate. But, if you  observe and use it, you may be surprised how accurate it is. I hope you've enjoyed this segment.

Before I go I thought I would share this, As a horse owner I've always found this useful

If the tail is dry -- the weather's clear

If the tail is wet -- it's raining
If the tail is white -- it's snowing
If the tail is burning -- it's hot
If the tail is horizontal -- it's windy
If the tail is gone -- there's a hurricane
If the horse is gone -- there's a tornado!

:-)




Rebecca Ladd

P.S. From Andy: I thought I would add an additional thought or two to this awesome blog post from Rebecca. You can also use wind directions and your barometer for( if you have one) to predict your local weather for a period of 24-36 hours in advance with reasonable accuracy. Here is a link to a wind-barometer table:

Wind-Barometer Table

Also the sequence of cloud types can also give you a clue as to what type of a weather system will be heading your way. You can also use wind direction and cloud type to aid you in your forecast too. I'll add all this over the next few days!


AG

This and That.

Starting Thursday, we will be in a prolonged period of wet weather.  The GFS and Euro agree that it will be wet. However, they disagree on the amount of rain we will be getting.  The GFS is showing rainfall amounts that are less than the Euro. The cut off low will have a Southerly flow that will be streaming up moisture into the area. we will have two main periods of rainfall. the first will be Wed night into Thur; the rain doesn't look like it will be all that bad. The 2nd event looks to be Fri Night. We look to see rainfall amounts that could  be as high as 1.5 - 2.0 inches. Saturday thru Tuesday will see off and on rain that will add to the totals.

                          Here is the GFS Accumulated precipitation forecast for Saturday

The Tropics

Still watching invest 98L in the central Atlantic. The system has become fairly well orginized. but it needs the  broad scale circulation to tighten up a bit now before it can close off fully and be declared a tropical depression. it is almost to that stage now, so it should become a named system by tomorrow.  The environment supports some strengthening until about 55W. at the point wind shear increases. and it will be sheared by the  upper-level westerlies. This shear will likely remain around the northeast Caribbean for the next week, making it difficult for 98L to strengthen much beyond a moderate tropical storm, It will be like Maria in the regard that a hurricane seems unlikely.  The track of 98L is fairly straight forward. A WNW track towards the leeward Antilles to the south of the subtropical ridge should be the rule for the next few days, with a more NW turn occurring west of 65W, probably taking 98L into Puerto Rico and Hispaniola.

There are signs that the  Caribbean might become active in 10-15 days, high pressure over eastern North America will stimulate surface convergence in the western Caribbean and allow a storm to try to form.

My Initial winter 2011-2012 thoughts.

With the feel of fall in the air our thoughts ineptly drift to winter and what it will bring.  The current pattern we're starting to experience is a very typical fall pattern. Now while it is too early for making a winter outlook/forecast. It's not too early to start looking at the way the pattern is setting up.  By the middle to end of November the winter pattern will be more or less locked in. The winter pattern starts with a strengthening jet as it makes it's migration south. Something we're just starting to see.  How the jet acts and sets up effects how the troughs will act and move during the winter.  Most agree that the winter of 2011-2012 will see the return of a moderate La Nada. The long range models are supporting this idea, more or less. In fact, looking at the sea surface temps show the La Nina is starting to strengthen. If this is the case, then the key to our upcoming winter will be the return of some strong high pressure blocking over northeastern Canada. The good news is the Euro long-range does not show much if any high pressure setting up over NE Canada. The Bad news is Last year's Euro long range showed some blocking but nowhere near as strong as what actually setup .  Last year was a La Nana and we all know how that turned out. Now if the Euro is right we won't have a block setup this year. This would mean just to our north, in places like Ontario and southern Quebec they would see tons of snow; while we had a warmer than normal winter with more or less normal snowfall. 

There are many such ways people try to use in forecasting long range weather events.  

There is a interesting theory called Lezak's recurring Cycle (LRC), many people don't but much stock in it, But I feel it does have things of interest. So first what the heck is the LRC. Well basically  he believes each year a unique weather pattern will set up between October 1st and November 10th. Lezak believes  once the pattern becomes established it cycles, repeats, and continues through winter, spring and into summer It isn’t just one long-wave trough, storm system, or ridge. It is a sequence of troughs and ridges that are cycling across the Northern Hemisphere within the Prevailing Westerly’s. I've looked back at past winters and feel some of what he is saying has merit. I have seen how it tracked “the storm” in last year's pattern, I have seen how it was responsible for how one area was affected by an event and another wasn’t. But it is still  just a theory about large scale upper air patterns using longwave positions to track 500mb vortices paths. Nothing in this theory talks about surface impact.

There's also a technique used with  Hovmoller diagrams that people try to use in forecasting long range weather events.  This gets very complicated, but it uses Hovmoller Diagrams for Long Range Forecasting of Significant Weather Events . Long range forecasters study the 500 mb height anomalies where they look for atmospheric signals and long wave anchors around the hemisphere. When viewed through wave theory principles, and in conjunction with Fast Fourier Transform applications, a forecaster can theoretically predict Arctic Outbreaks, strong frontal passages, and even severe weather events.

I just thought I would bring this to your attention......I do find them interesting from a forecasting standpoint. Anyway, back to the Jet stream and troughs.

Most of the time you can get an idea of how winter is going to shape up starting now and thru October,  Therefore, I always try to get a feel for the long term pattern around this time. what I'm starting to see is that the trough axis will be such that the Appalachians and into the  NEUS could see quite a bit of snow. The trough axis is the average axis of the troughs that will be  developing during the winter. It acts as the steering mechanism for inland and coastal storms.

   

At this time, this is how I see the trough axis setting up.  Remember, this is not my official outlook / forecast;  I will issue that in about 6 weeks. The axis will end-up looking different due to the effect of such things as the amplitude of the flow, but I do think, it will be close to what I show in the above chart. A trough axis like this would allow a few inland and coastal bombs to move into the NEUS. I will keep watching the pattern over the next 5-6 weeks And make changes as necessary, before I come to a final long range consensus.

Rebecca Ladd

Katia, Maria, and Nate

Katia:

Hurricane Katia is  moving north. She should change direction and start to move out to sea tomorrow. Katia will stay south of New England and well south of the Canadian Maritimes.

                                                Forecasted track for Katia

Tropical rainstorm Lee:

The upper trough associated with what's  left of Lee will be spinning around with no place to go. Until a trough moves out of Canada to get rid of it in a few days. The flooding in the Twin Tiers and Mohawk Valley is historic. When all is said and done some places in the Susquehanna Valley will see upwards of one foot of rain.

Maria:

At this time TS Maria is moving W. She is 2 days away from impacting the northern Leeward Antilles Islands and Puerto Rico. Maria is struggling with some dry air. The environment is fairly conducive with just a bit of shear. The shear will keep her disorganized for the Next few days . So, we won't see any rapid strengthening. In a few days when she starts to make a turn more to the north; the environment will become much more supportive for more in the way of strengthening. I would say Maria has a good shot at reaching hurricane status in about 110 - 120 hrs. However, she will most likely lose her hurricane status within 48 hours do to the return of shear. It is still way too early to forecast a track along the east coast. However, Maria could be a threat to the SEUS in 10 days or so.

                                

                                        Model forecast track for Tropical Storm Maria

                                                     GFS ensemble members

Nate:

TS Nate is still pretty much stationary. This is because of several ridges that have it blocked in. The models are split on where Nate is going. I know Andy felt at least yesterday that Nate was a Mexican storm. Now why this is still a good possibility, I'm not so sure this will be the case. There is a lot of dry air NW of Nate. And there is weakness in the trough north of Nate. I think the ridge will remain west of Nate. So with the Atlantic ridge  giving it a path to exploit this weakness. This could have a impact on the track. It seems that the GFS has noticed this set-up. The GFS had the storm going into Mexico yesterday. However, it now turns Nate NNE toward the SEUS. However, the Euro now shows Nate moving into Mexico. So it will be a wait and see.

Model forecast track for Tropical Storm Nate

                                                                                          

                                               GFS ensemble members 

Rebecca

Wet weather continues.

 The upper-level pattern has not been completely kind lately. The remains of Lee will become part of a upper-level low. This ULL will become detached tomorrow from the main jet stream. Once it's cut off it will sit in the Ohio Valley until it dissipates. The models have been having a hard time pin pointing where the heaviest rain will be. It looks like Ccentral Pennsylvania and into southern New York look like will be the most threatened with flooding. In NYS the steadiest of the rainfall looks to be from the Finger Lakes into Central NYS. The WRF and GFS bring 3-5” of rainfall across Central New York and Finger Lakes. TS Lee has been playing mischief for the last couple of days; Lee contributed to a tornado and the other severe weather we've seen. The pattern we're in will not be changing quickly. As for Eastern NYS and the Capital District (CD), There will be some moisture drawn in from the Atlantic, The GFS shows heavier rain in northern New Jersey into New York City. Some of the other models don't show this. Right now it looks like the CD will see 1-3". The point I'm making is the region cannot stand very much rain before flooding resumes. So things will have to be watched.

QPF forecast

As for Katia,  Right now she is a Cat 3. She seems to be doing what was discussed in the other blog post. she is going to scare the outer banks of NC and maybe flirt with Cape Cod.  But, I think that is it. The ULL is not all bad;  it will push Katia back;  where she will dance with high pressure over the Atlantic. Once she is caught up in the westerly's  she moves out to sea well south of New England and the Canadian Maritimes.  She should cause large swells up and down the East Coast beaches. So beach erosion and rip currents will be an issue.

Rebecca

Update on Katia and Lee.

Good morning everyone..This is just a quick update on the tropical systems.. hope everyone has a great Sunday. Katia dropped to a Tropical Storm Again overnight. However once again she as bounced back to a hurricane.  The reason for this up and down, the dry air I talked about in the last blog on the tropical systems. I have noticed that winds might be understated in katia. same buoy reports winds sustained 71.9KTS gusting to 89.4KTS - that equates approximately to 80MPH gusting to 105MPH. This is one of those uncommon instances where the Dvorak T-numbers ( estimates of tropical cyclone intensity based only on satellite images)  understated the wind speeds. The only reason I mention this is because of the media  attention about winds in Irene being overstated and here is an instance where in the absence of a recon flight providing real time data from the center there will be times where the strength is stronger than what it appears. The models keep bringing Katia westward. But like I said in the last blog, Katia would come close enough to scare the east coast. It's still too early to talk about east coast landfall.....But, I still feel Katia will not make a landfall. There are two reasons I feel this way. One is the Trough that should be in-place enough to force Katia to recurve back out to sea. The second is a upper level low (ULL) in the Tennessee Valley. If Lee get involved with this ULL and hangs out long enough in the Tenn. Valley then he will serve to help steer Katia along the coast. If Lee isn't effected by the ULL then Lee would move toward the NEUS a little quicker. Once Lee was in the NE he would help push Katia away from the coast. Either way, Lee is a contributing factor to the eventual path of Katia. It's all intertwined. I'm beginning to think Katia will not reach Major hurricane status. This is impotent because as a Cat 3 she could have pushed back on the trough. moving closer to the east coast.

Lee

Tropical Storm Lee is still just off the coast of LA with winds down a little. Some of the moisture associated with Lee will be pulled up into NYS on Monday, The moisture will interact with a slow moving cold front.  This will enhance the rainfall With some areas seeing fairly substantial rainfall. There is uncertainty as to just where the heavier bands will set-up....I think the heavier rain will be just west of the Capital Distract (but this is in no-way certain).  At this time it looks like Lee will track up over the  Appalachians or just west of them.  Lee could be approaching the Area on Thursday. As for how much rain he drops, it would depend on how fast he dissipates over land.

 This is an image of the upper air patterns. You can plainly see the steering patterns for both tropical systems. 

                                   Spaghetti  tracks of both systems.

QPF outlook

Rebecca

Early analyses of Katia, Lee, other things of interest.

The Atlantic basin (The Atlantic and Caribbean) took its time to produce a hurricane this year. However, as we're all unfortunately aware, that all came to an end last week.  Now One week after Irene, we have Katia starting to flex her muscles , newly named Lee in the GOM (Gulf Of Mexico), a low pressure system south of Halifax Nova Scotia that is being monitored.  What I'm going to try to do is sort it out a bit....and give a little insight into how things look at this early stage.  Mind you things can and most likely will change next week....this analyses will be a good overview of how it looks at this time; it will set the stage for  more later... when more detailed information and better model data become available.

First, how is a forecast made? I can't speak for anyone but myself. However, this is how I do it.  I was taught that when making a forecast;  the first thing I had  to do was get a feel of what's going on. Then apply  my insight and knowledge on how I thought things would unfold weather-wise (I guess sort of hearing what the storm is thinking). Then and only then, should I look at the weather models. After looking at the models I would apply what I knew about their strengths and weaknesses, then based on that  throw out model runs that didn't look right.  Then watch the existing  models a bit and see if they trend toward my original thinking...If they do I'm on the right track. IMO this makes how the storm unfolds easier to understand and makes the forecast much more accurate.  Also, you don't want to spend all your time watching the models. I feel it's better to see how the atmosphere is responding to what's going on. If you know what you're doing you should pick things up faster than the models will. Remember models are only a tool....a  forecast is based on many things not the least of which is a feeling.

Katia:

Katia was downgraded to a tropical storm during the overnight , However, She  regained her status as a hurricane this morning,  The downgrade happened because of the dry to her north. This dry air as been effecting Katia for a few days. it's been what's been keeping her growth in check. However, she is now over waters that are more inductive of intensification. The National Weather Service was her moving in a west-northwesterly direction. We will see strengthening over the next few days. Katia is  expected reach major hurricane status by early next week. The models continue to shift farther west, as does the forecast track. At this time Katia looks to track west enough to give us a scare at least. As of right now, there were no coastal warnings or watches in effect for the east coast.

Lee:

As of this morning Tropical Depression 13 now has the name Lee. An upper low over southwest Louisiana to the northwest of the storm is still imparting some shear  , but not as much as yesterday. Also, there is dry air that is affecting the storm . All of this is responsible for Lee's lopsided look . Lee's outflow is very limited on the western side; with most of the convection off to the eastern side, it should  keep the storm from intensifying  too quickly.   The storm looks to dump between 10 to 15 inches of rain on much of the Louisiana, Mississippi and Alabama coastlines.This is because Lee is moving extremely slow ( at this time 2 mph). So what does this have to do with  Upstate NY and New England? Right now, it looks like next week  moisture from TS Lee in Louisiana  might move up a front that should stall. Some of the models are showing  1-4" totals from the Mid Atlantic up into New England.

                                             QPF forecast for the next 5 days

First off we're going to have rain / t-storms this weekend. Some of the thunderstorms could drop locally heavy rain fall.  If we tap into any moisture from Lee/Katia it would make things that much worse.  

As for Katia and Lee, This is in no-way a forecast, this is where my thinking is right now. We are way to far out for track forcast. However, here is a general overview of what could happen

1) If the trough takes too long  to establish itself in the east. Katia come far enough west to brush the Outer Banks of NC.....this would be similar to Irene.  However, she most likely would move out to sea before a landfall and go out to sea. That said she would still bring heavy rainfall to the Mid Atlantic states.  In this scenario Lee would most likely dissipate in the SEUS.  

2)  If the trough reaches the east in time Katia would be turned  out to sea. However,  Lee  could sneak behind the trough and move NE. Most likely staying just west of the Appalachians. which would bring heavy rain into both western PA and NYS

3) WE also could end up with both systems effecting us. If Lee tracks over or just east of the Appalachians and Katia comes fairly close to the east coast  we would have rain from both systems.

At this time I see no way the tropical systems would give us the kind of rain we saw with Irene. However, do to the historic flooding we've already seen....rainfall of 3-5 inches would have a huge impact.

Other things of interest:

Invest 94L  Is a low pressure system located about 460 miles south-southeast of Halifax Nova Scotia . upper level winds are becoming unfavorable , however it still has a medium chance (40%) of becoming a tropical system. I think this system will fall apart over the next few days....but their is a chance I could be wrong........regardless of what it does...it would have no impact on us.

Like I said,  Katia is too far out to forecast a track along or near the east coast. However, I think she will come close enough to scare us.  but not make a US landfall.  Right now, I'm more worried about possible rain from Lee than anything from Katia. Things will most likely change in the next few days.......I will keep you up to date as I get a better feel for what's going to happen.


Rebecca