ATL: INVEST 90L - Models

[weatherwindow]

According to nws/mia and HPC, SFla is under a zone of deformation which apparently will enhance rainfall during next week in concert with the disturbance out of the GOM...can someone explain the term: zone of deformation..Thanks, Rich

http://forecast.weather.gov/product.php ... glossary=1

Deformation Zone
The change in shape of a fluid mass by variations in wind, specifically by stretching and/or shearing. Deformation is a primary factor in frontogenesis (evolution of fronts) and frontolysis (decay of fronts).

Basically, this enhances upward motion across S FL, meaning increased moisture convergence and precipitation if the thermodynamics are ripe.
http://w1.weather.gov/glossary/index.php?letter=d

Google is your friend.

Thanks..however I need an explanation of meteorological mechanics involved..can you elaborate?

[MiamiensisWx]

Yes I saw your post on the other thread and you have the right train of thought. By the way I think you meant "right-entrance" region instead of right-exit. That is the part that provides large scale ascent. However, 200mb winds although in the same direction, may simply be too strong. You can still have speed shear. I see 200mb winds of 45-60 knots in the eastern Gulf in 48-72 hours. So even if you have 20 knots of wind at 850mb in the same direction then shear is still 25-40 knots. It may be too much to allow a surface circulation to develop. However, there will probably be a large area of upper-level divergence which will promote rising motion and convection. Notice how the 00Z Euro didn't really develop a consolidated low, but instead strung out 850mb vorticity in a elongated SW-NE area. I'm growing skeptical of anything developing, and if it does, it will most likely be the typical June sheared mess.

Thanks for the response and the explanation. Perhaps the 00Z ECMWF also shows less development than it did at 12Z yesterday because it greatly delays the ejection of the low from the Bay of Campeche. This means that it faces greater shear by the time it enters the Gulf, as the UL anticyclone gets displaced to the south of Cuba and the UL trough amplifies.

[Dean4Storms]

12z GFS thru 132hrs doesn't develop and doesn't much move the low from the central Gulf.

@ 153hrs Broad Low along North Florida East Coast.

[cycloneye]

Horrible model consistency going on.The only model showing any real consistent develop is the CMC-GEM. Either drop it entirely or develop it instead of flipping each run and making 90L into a disorganized trough with several lows. I suspect the models will get a better grip on this situation as we move closer to the predicted time of genesis.

[cycloneye]

Here is the extended discussion from HPC about the scenarios of the models.

SUPER-MOISTURE-PACKED
TROPICAL AIR CIRCULATING AROUND A DEEP-LAYER VORTEX OVER THE GULF
OF MEXICO IS EXPECTED TO WASH INTO SOUTHERN FLORIDA AS THE PASSAGE
OF A SHORTWAVE TROUGH ACROSS THE EASTERN UNITED STATES ELONGATES
THE GULF CIRCULATION. ALL THE MODELS BREAK OFF A CHUNK OF THIS
TROPICAL SWIRL AND TRACK IT ACROSS THE FLORIDA PENINSULA, THEN UP
THE SOUTHERN EDGE OF THE POLAR WESTERLIES ALONG THE SOUTHEAST
COAST. THE GEM GLOBAL CONTINUES TO PRESENT AN UNREALISTIC
EMERGENCE OF A FULL-BLOWN TROPICAL CYCLONE VERY EARLY IN THE
PERIOD, TRACKING IT ACROSS FLORIDA THEN UP THE ATLANTIC COAST
PLAIN--DIRECTLY ASTRIDE THE BAROCLINIC ZONE IN PLACE. THE MOST
LIKELY OUTCOME IS A JUICY FRONTAL WAVE THAT SHOULD KEEP MOST OF
THE HIGHEST MOISTURE-CONTENT AIR EAST OF THE ATLANTIC COAST NORTH
OF JACKSONVILLE, FLORIDA. THE 0.25KM ECMWF PUSHES A SLUG OF 2.50+"
PRECIPITABLE WATER-LADEN AIR ACROSS SOUTHERN FLORIDA, INCLUDING
THE KEYS, NEXT WEDNESDAY THROUGH THURSDAY, SUPPORTING MANY INCHES
OF RAINFALL ACROSS THE AREA. WILL BE COORDINATING WITH THE
NATIONAL HURRICANE CENTER ON THE FIRST MEDIUM-RANGE HOTLINE CALL
OF THE YEAR EARLY THIS AFTERNOON TO DISCUSS ANY TROPICAL CYCLONE
POTENTIAL WITH THIS SYSTEM, AS WELL AS ANY OTHERS OVER THE NEARBY
OCEANS.


CISCO
http://www.hpc.ncep.noaa.gov/discussion ... isc=pmdepd

[jlauderdal]

Here is the extended discussion from HPC about the scenarios of the models.

SUPER-MOISTURE-PACKED
TROPICAL AIR CIRCULATING AROUND A DEEP-LAYER VORTEX OVER THE GULF
OF MEXICO IS EXPECTED TO WASH INTO SOUTHERN FLORIDA AS THE PASSAGE
OF A SHORTWAVE TROUGH ACROSS THE EASTERN UNITED STATES ELONGATES
THE GULF CIRCULATION. ALL THE MODELS BREAK OFF A CHUNK OF THIS
TROPICAL SWIRL AND TRACK IT ACROSS THE FLORIDA PENINSULA, THEN UP
THE SOUTHERN EDGE OF THE POLAR WESTERLIES ALONG THE SOUTHEAST
COAST. THE GEM GLOBAL CONTINUES TO PRESENT AN UNREALISTIC
EMERGENCE OF A FULL-BLOWN TROPICAL CYCLONE VERY EARLY IN THE
PERIOD, TRACKING IT ACROSS FLORIDA THEN UP THE ATLANTIC COAST
PLAIN--DIRECTLY ASTRIDE THE BAROCLINIC ZONE IN PLACE. THE MOST
LIKELY OUTCOME IS A JUICY FRONTAL WAVE THAT SHOULD KEEP MOST OF
THE HIGHEST MOISTURE-CONTENT AIR EAST OF THE ATLANTIC COAST NORTH
OF JACKSONVILLE, FLORIDA. THE 0.25KM ECMWF PUSHES A SLUG OF 2.50+"
PRECIPITABLE WATER-LADEN AIR ACROSS SOUTHERN FLORIDA, INCLUDING
THE KEYS, NEXT WEDNESDAY THROUGH THURSDAY, SUPPORTING MANY INCHES
OF RAINFALL ACROSS THE AREA. WILL BE COORDINATING WITH THE
NATIONAL HURRICANE CENTER ON THE FIRST MEDIUM-RANGE HOTLINE CALL
OF THE YEAR EARLY THIS AFTERNOON TO DISCUSS ANY TROPICAL CYCLONE
POTENTIAL WITH THIS SYSTEM, AS WELL AS ANY OTHERS OVER THE NEARBY
OCEANS.


CISCO
http://www.hpc.ncep.noaa.gov/discussion ... isc=pmdepd

super moisture packed, sounds like an efficient rain maker in the cards

[tropicwatch]

Great, that would mean very little rain for NW Florida.

[ronjon]

12z CMC = up through Tampa Bay northeast toward Daytona as 1000 mb low.

http://raleighwx.americanwx.com/models/ggem/12zggemtropical850mbVortSLPGGEMLoop.html

[gatorcane]

12Z ECMWF 144 hours shows the area of low pressure moving NE into the west coast of Florida:

[SouthFloridawx]

Are there any Model Plots for 90L?

[cycloneye]

Are there any Model Plots for 90L?

Not yet but as the timeframe narrows,they will start to run the BAMS.

[OuterBanker]

Lol, what a difference a day makes. GFS has totally abandoned it. After Florida safely offshore and doesn’t even seem to have a cloud in it, much less tropical. Euro is weaker, still close to shore, but it’s waffling between the 00z and 12z runs. Only the Canadian seems to be consistent. We are really grasping at straws when we quote the Canadian.
So, let me get things started early.

Season over!

[Aric Dunn]

Lol, what a difference a day makes. GFS has totally abandoned it. After Florida safely offshore and doesn’t even seem to have a cloud in it, much less tropical. Euro is weaker, still close to shore, but it’s waffling between the 00z and 12z runs. Only the Canadian seems to be consistent. We are really grasping at straws when we quote the Canadian.
So, let me get things started early.

Season over!

not sure what gfs your looking at but it has it. the gfs often has a weak reflection even with a hurricane. but it still showing something.

http://mag.ncep.noaa.gov/list_files_are ... wnd_precip

[OuterBanker]

Aric, apparently I’m looking at the near surface mslp and precip. This is available through WeatherBell. Now that I have you, what are the best of each of the models. They do seem to have them all. And a short explanation of each (just the ones you recommend) would be greatly appreciated.

[Aric Dunn]

Aric, apparently I’m looking at the near surface mslp and precip. This is available through WeatherBell. Now that I have you, what are the best of each of the models. They do seem to have them all. And a short explanation of each (just the ones you recommend) would be greatly appreciated.

They all offer a perspective. though the consensus with the gfs and euro is your best bet and besides the intensity they are in general in agreement on something developing how organized and strength remains to be seen. they all should come more into agreement when there is a actual disturbance to focus on.

[MiamiensisWx]

18Z GFS shows somewhat greater organization and convection closer to the center in two days.

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_054_10m_wnd_precip.gif

Compare to the same time-frame on the 00Z run from yesterday:

http://mag.ncep.noaa.gov/gfs/00/gfs_wnatl_072_10m_wnd_precip.gif

By Tuesday, nevertheless, it gets sheared apart.

[Aric Dunn]

18Z GFS shows somewhat greater organization and convection closer to the center in two days.

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_054_10m_wnd_precip.gif

Compare to the same time-frame on the 00Z run from yesterday:

http://mag.ncep.noaa.gov/gfs/00/gfs_wnatl_072_10m_wnd_precip.gif

was just about to post about that. other thing to notice the low develops in the next 36 to 48 hours. which coincides with the current energy entering the southern gulf.

[MiamiensisWx]

18Z GFS shows somewhat greater organization and convection closer to the center in two days.

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_054_10m_wnd_precip.gif

Compare to the same time-frame on the 00Z run from yesterday:

http://mag.ncep.noaa.gov/gfs/00/gfs_wnatl_072_10m_wnd_precip.gif

was just about to post about that. other thing to notice the low develops in the next 36 to 48 hours. which coincides with the current energy entering the southern gulf.

It also shows less shear (less than 30 kt) near the center in three days. This is a fairly significant shift from what the 00Z run showed.

18Z 200 mb (only about 25 kt of shear): http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_072_200_wnd_ht.gif

00Z 200 mb (35-40 kt of shear): http://mag.ncep.noaa.gov/gfs/00/gfs_wnatl_090_200_wnd_ht.gif

The shear gets even lower in four days! Note only 20-25 kt of shear over the low-level center:

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_090_200_wnd_ht.gif
http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_090_10m_wnd_precip.gif

[Aric Dunn]

18Z GFS shows somewhat greater organization and convection closer to the center in two days.

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_054_10m_wnd_precip.gif

Compare to the same time-frame on the 00Z run from yesterday:

http://mag.ncep.noaa.gov/gfs/00/gfs_wnatl_072_10m_wnd_precip.gif

was just about to post about that. other thing to notice the low develops in the next 36 to 48 hours. which coincides with the current energy entering the southern gulf.

It also shows less shear (less than 30 kt) near the center in three days. This is a fairly significant shift from what the 00Z run showed.

18Z 200 mb (only about 25 kt of shear): http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_072_200_wnd_ht.gif

00Z 200 mb (35-40 kt of shear): http://mag.ncep.noaa.gov/gfs/00/gfs_wnatl_090_200_wnd_ht.gif

The shear gets even lower in four days!

gfs keeps it on the gulf beyond 4 days... look like the trough does not pick it up right away.

[MiamiensisWx]

gfs keeps it on the gulf beyond 4 days... look like the trough does not pick it up right away.

The trough axis does catch it...the model shows landfall near Bradenton as a strong depression in five days:

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_123_10m_wnd_precip.gif

Huge rain event for S half of FL:

http://mag.ncep.noaa.gov/gfs/18/gfs_wnatl_123_precip_ptot.gif

Overall, the precipitation shield is shaped much like Barry's in 2007. That TC followed a very similar track to that of the GFS solution.