Models Develop a Disturbance Near Florida (Is invest 90L)

[Derek Ortt]

The Canadian,

I suspect the reason it is as aggressive is that a few years ago they changed from a 1 degree to a .6 degree resolution. I wonder if they didnt properly change some of the paramaterizations

I'll say this much, if the Canadian is correct and we see Ike reborn in the GOM this week... I'll do mountain time trials up the Ventoux until I can beat Armstrong's TDF time from 2002

[Aric Dunn]

The Canadian,

I suspect the reaosn it is as aggressive is that a few years ago they changed from a 1 degree to a .6 degree resolution. I wonder if they didnt properly change some of the parametrization

I'll say this much, if the Canadian is correct and we see Ike reborn in the GOM this week... I'll do mountain time trials up the Ventoux until I can beat Armstrong's TDF time from 2002

actually Derek i mentioned this before a few pages back...
it may or may not play a role in what you say but they actually found a sign error last year in there code that they recently fixed. lol

[cycloneye]

12z UKMET Text plots

Sun May 17 14:04:19 EDT 2009



955

WTNT80 EGRR 171800


MET OFFICE TROPICAL CYCLONE GUIDANCE FOR NORTH-EAST PACIFIC

AND ATLANTIC

GLOBAL MODEL DATA TIME 12UTC 17.05.2009

NEW TROPICAL STORM FORECAST TO DEVELOP AFTER 36 HOURS
FORECAST POSITION AT T+ 36 : 25.9N 79.8W

VERIFYING TIME POSITION STRENGTH TENDENCY
-------------- -------- -------- --------
00UTC 19.05.2009 25.9N 79.8W WEAK
12UTC 19.05.2009 25.9N 79.0W MODERATE INTENSIFYING RAPIDLY
00UTC 20.05.2009 26.5N 79.4W MODERATE INTENSIFYING SLIGHTLY
12UTC 20.05.2009 27.9N 80.3W MODERATE WEAKENING SLIGHTLY
00UTC 21.05.2009 26.5N 83.5W MODERATE WEAKENING SLIGHTLY
12UTC 21.05.2009 26.7N 83.5W MODERATE LITTLE CHANGE
00UTC 22.05.2009 27.2N 84.2W WEAK WEAKENING SLIGHTLY
12UTC 22.05.2009 28.1N 84.7W WEAK WEAKENING SLIGHTLY
00UTC 23.05.2009 29.0N 85.8W MODERATE INTENSIFYING SLIGHTLY
12UTC 23.05.2009 30.0N 87.9W MODERATE INTENSIFYING SLIGHTLY


THIS INFORMATION IS PROVIDED AS GUIDANCE FOR TROPICAL CYCLONE
RSMCS. IT REQUIRES INTERPRETATION BY TROPICAL CYCLONE SPECIALISTS
AND SHOULD NOT BE CONSIDERED AS A FINAL PRODUCT


MET OFFICE, EXETER, UK

TOO 171636

http://my.sfwmd.gov/sfwmd/common/images ... /ukmet.txt

[gatorcane]

Tropical Weather discussion snippet about this feature, note a mid-level rotation working down to the surface to form a surface low is mentioned.

000
AXNT20 KNHC 171748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAY 17 2009

CARIBBEAN SEA...
A MIDDLE TO UPPER TROUGH OVER THE WRN CARIBBEAN ALONG WITH A
SURFACE TROUGH EXTENDING FROM CENTRAL CUBA ALONG 79W TO NEAR 16N
IS PRODUCING SCATTERED SHOWERS AND TSTMS N OF 16N BETWEEN
74W-79W. LIGHTNING DATA SHOWS THE GREATEST CONCENTRATION OF
STRIKES OVER THE ADJACENT WATERS BETWEEN ERN JAMAICA AND SW
HISPANIOLA. LATEST VISIBLE SATELLITE IMAGES AND GLOBAL MODEL
DATA INDICATE CYCLONIC ROTATION IN THE MID-LEVEL FIELDS ALONG
79W JUST S OF CUBA. THIS FEATURE MAY BUILD CLOSER TO THE SURFACE
OVER THE NEXT COUPLE OF DAYS AND DRIFT GENERALLY NWD...
CONTINUING THE THREAT FOR SCATTERED SHOWERS AND TSTMS OVER THE
N/CENTRAL CARIBBEAN

http://www.nhc.noaa.gov/text/refresh/MI ... 1748.shtml?

[cycloneye]

Latest 72 hour forecast from TAFB.It looks like they are going with GFS and UKMET on the track.

[wxman57]

Never a dull moment in Canadian land...

http://moe.met.fsu.edu/tcgengifs/cmc/20 ... /slp24.png

As usual, the Canadian focuses on development beneath the upper low.

[tolakram]

I can't believe anything will develop, and I can't see shear being reduced at all. We'll see.

[Derek Ortt]

I think I've seen a whole 1 storm develop directly underneath an upper low in the GOM

That would be Barry 2001

Development directly underneath a UL is common for June/July systems in the north Atlantic (Arlene 1999), ot late season systems

[jinftl]

Would a system that is not warm core in nature, which this very well may be, really be so dependent on warm water. I mean, look at the nor'easters that develop off of New England in winter....some of those can have pressure and wind readings akin to many hurricanes. Warm enough water may be key to warm-core, tropical development....but would 50mph winds and driving rain from a sub-tropical or hybrid system be different than 50mph winds and driving rain from a tropical storm?

On a side note (probably should be posting a separate thread...sorry folks), i would be very curious to know what allowed Hurricane Able in May 1951 to become a Cat 2 in water that was probably in the 75-80 range (gauging it by current water temp at 30N,75W) and then a Cat 3 in water than was probably in the high 60's to mid-70's at most (as estimated by current water temps around 35N,75W).

From just yesterday, 80 degree water has now reached the panhandle beaches in places...buoy readings off of panhandle up about 2 deg from yesterday

well here is some sst measurements for the eastern Gulf
http://www.nodc.noaa.gov/dsdt/cwtg/egof_tmap.html

lol.. yes but dont forget the ocean moves and the sun can only warm it so fast and to a very shallow depth .. i mean like a few inches in one day. your tallking the immediate top layer of the ocean and then is mixed down and that cycle heats the ocean to greater depths over time. if anything were to move over those areas now you would not have a lot of time before up welling occurred.. so any major intensification do to ssts is really not likely ..

and actually i did a small calculation yesterday to see how long it would take the sun to warm the ocean ( without much mixing and only the area of the NE gulf) and it was like 3 1/2 degrees over a 3 month period and was to a depth of 3 meters which is a large volume of water. so those bouys are going to go up and down based on currents .. but yeah its clearly warming up but its going to take a while to get to a depth that would sustain any intensity over TS.

[gatorcane]

As for shear, GFS vertical shear forecasts lightens the shear in the Straits of Florida and off the east coast of FL starting around 72 hours, allowing a small window for something to maybe get going:

[MiamiensisWx]

NEXRAD,

Your analyses are always excellent. However, I must disagree with you in regard to the track. The ECMWF has always harbored a notorious bias: it has a tendency to exhibit greater amplification of specific mid/upper level patterns. Recently, the GFS has outperformed the ECMWF in some cases. At this time, the ECMWF is the only reliable model that indicates a track over or west of southern Florida. Several 12Z GFS ensembles suggest that greater baroclinicity will be present near the east coast of FL. They are also substantiated by the UKMET. The fact that the ECMWF is closer to the 00Z NAM diminishes its credulity; in fact, even the NAM has recently shifted considerably farther east. This trend is a product of (1) the greater baroclinicity off E FL and (2) greater vorticity associated with a deeper longwave exiting the eastern United States. Of course, this trend would also lead to a stronger mid level ridge, which explains the models' sharp westward turns into central FL. Therefore, I tend to believe that the precipitation over south FL will be lower than your expectations, and I do not see the tornado threat that would be supported by a track farther S and W.

What are your latest thoughts?

Edit: As an aside, why are there comparisons to Able of 1951? That TC was associated with a different synoptic pattern.

[Derek Ortt]

what allowed Able to become a cat 3 is likely an awful HURDAT record

[cycloneye]

Floater 1 over it.



http://www.ssd.noaa.gov/PS/TROP/floaters.html

[hurricanefloyd5]

is it me or do I see some banding starting to form over the Island of Jamaca on the last 2 frames or so??????????http://www.goes.noaa.gov/HURRLOOPS/huirloop.html

[Aric Dunn]

Would a system that is not warm core in nature, which this very well may be, really be so dependent on warm water. I mean, look at the nor'easters that develop off of New England in winter....some of those can have pressure and wind readings akin to many hurricanes. Warm enough water may be key to warm-core, tropical development....but would 50mph winds and driving rain from a sub-tropical or hybrid system be different than 50mph winds and driving rain from a tropical storm?

On a side note (probably should be posting a separate thread...sorry folks), i would be very curious to know what allowed Hurricane Able in May 1951 to become a Cat 2 in water that was probably in the 75-80 range (gauging it by current water temp at 30N,75W) and then a Cat 3 in water than was probably in the high 60's to mid-70's at most (as estimated by current water temps around 35N,75W).

From just yesterday, 80 degree water has now reached the panhandle beaches in places...buoy readings off of panhandle up about 2 deg from yesterday


well here is some sst measurements for the eastern Gulf
http://www.nodc.noaa.gov/dsdt/cwtg/egof_tmap.html

lol.. yes but dont forget the ocean moves and the sun can only warm it so fast and to a very shallow depth .. i mean like a few inches in one day. your tallking the immediate top layer of the ocean and then is mixed down and that cycle heats the ocean to greater depths over time. if anything were to move over those areas now you would not have a lot of time before up welling occurred.. so any major intensification do to ssts is really not likely ..

and actually i did a small calculation yesterday to see how long it would take the sun to warm the ocean ( without much mixing and only the area of the NE gulf) and it was like 3 1/2 degrees over a 3 month period and was to a depth of 3 meters which is a large volume of water. so those bouys are going to go up and down based on currents .. but yeah its clearly warming up but its going to take a while to get to a depth that would sustain any intensity over TS.

[/quote]

well intensification can depend on a number of things .. if its a hybrid or subtropical ssts have been know to be below 80 .. in 2005 we have the hurricane form in the eastern atlantic in 76 degree water. also its speed plays a role, as well is baroclynic enhancement.

[ronjon]

12Z euro pretty much the same as the 00Z. SE GOM heading slowly N-NW to the northern gulf coast.

http://www.ecmwf.int/products/forecasts/d/charts/medium/deterministic/msl_uv850_z500!Wind%20850%20and%20mslp!120!North%20America!pop!od!oper!public_plots!2009051712!!/

[wxman57]

Would a system that is not warm core in nature, which this very well may be, really be so dependent on warm water. I mean, look at the nor'easters that develop off of New England in winter....some of those can have pressure and wind readings akin to many hurricanes. Warm enough water may be key to warm-core, tropical development....but would 50mph winds and driving rain from a sub-tropical or hybrid system be different than 50mph winds and driving rain from a tropical storm?

Coolish SSTs and wind shear would not adversely impact the development of a cold-core low.

[wxman57]

is it me or do I see some banding starting to form over the Island of Jamaca on the last 2 frames or so??????????http://www.goes.noaa.gov/HURRLOOPS/huirloop.html

Nothing there. No circulation, no banding, no low.

[cycloneye]

Miami AFD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
210 PM EDT SUN MAY 17 2009

.DISCUSSION...THE DILEMMA CONTINUES AS TO JUST WHAT KIND OF
WEATHER SYSTEM WILL BE AFFECTING SOUTH FLORIDA OVER THE NEXT FEW
DAYS. ALL MODELS AGREE THAT AS STRONG SHORT WAVE DIGS INTO THE
SOUTHEAST STATES, A MID LEVEL LOW WILL GET CUT OFF ON THE SOUTHERN
FRINGE OF THE TROUGH WITH SURFACE LOW DEVELOPING TO THE SOUTHEAST
BUT THEY ALL CONTINUE TO DISAGREE AS TO LOCATION AND TIMING OF
SUCH FEATURES. CURRENTLY, A WEAK MID LEVEL LOW APPEARS TO BE
CENTERED OVER CENTRAL CUBA WITH THE MODELS INITIALIZING THIS QUITE
WELL. LOOKING AT SURFACE STREAMLINE ANALYSIS, THERE ALSO APPEARS
TO BE A TROUGH JUST WEST OF THE CONVECTION OVER THE NORTH CENTRAL
CARIBBEAN. AS THE UPSTREAM TROUGH DIGS INTO THE NORTHEAST GULF OF
MEXICO, THE MID LEVEL LOW OVER CUBA WILL GET ABSORBED AND IT IS
THE SURFACE TROUGH THAT THE MODELS DEVELOP A CLOSED SURFACE LOW
FROM WITH THE NAM REMAINING THE FASTEST IN ITS DEVELOPMENT AND THE
ECMWF THE FARTHEST TO THE WEST. ONE THING IS NEARLY CERTAIN, NO
MATTER WHERE THE MID/SURFACE LOWS END UP BEING LOCATED, SOUTH
FLORIDA WILL HAVE AN INCREASE IN SHRA/TSRA ACTIVITY DUE TO THE
COLDER TEMPERATURES ALOFT AND AN INCREASE IN DEEP LAYER MOISTURE.
ANOTHER ISSUE IS THAT MET GUIDANCE HAS BEEN OUTPERFORMING MAV
GUIDANCE IN POPS FOR THE PAST FEW PERIODS. BUT CONSIDERING THE NAM
SEEMS TO BE DEVELOPING THE SYSTEM TOO QUICKLY, IS THIS TREND GOING
TO END WITH THIS CYCLE? ALL OF THIS BEING SAID, IT STILL REMAINS A
HIGHLY UNCERTAIN FORECAST ESPECIALLY FOR RAINFALL TOTALS NOT TO
MENTION THE LOCATION OF THE HIGHEST AMOUNTS. THE OTHER FACTOR IS
THE WIND DIRECTION. DEPENDING ON WHICH MODEL TURNS OUT MORE
CORRECT, THE GFS AND NAM FOR LATE TUESDAY AND TUESDAY NIGHT ARE
180 DEGREES APART JUST DUE TO THE FORECAST POSITION OF THE SURFACE
LOW. SO IT APPEARS AT THIS POINT THE BEST COURSE OF ACTION IS GO
STATUS QUO AND CONTINUE WITH THE HIGHER CHANCES FOR RAINFALL.

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

[Aric Dunn]

Miami AFD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
210 PM EDT SUN MAY 17 2009

.DISCUSSION...THE DILEMMA CONTINUES AS TO JUST WHAT KIND OF
WEATHER SYSTEM WILL BE AFFECTING SOUTH FLORIDA OVER THE NEXT FEW
DAYS. ALL MODELS AGREE THAT AS STRONG SHORT WAVE DIGS INTO THE
SOUTHEAST STATES, A MID LEVEL LOW WILL GET CUT OFF ON THE SOUTHERN
FRINGE OF THE TROUGH WITH SURFACE LOW DEVELOPING TO THE SOUTHEAST
BUT THEY ALL CONTINUE TO DISAGREE AS TO LOCATION AND TIMING OF
SUCH FEATURES. CURRENTLY, A WEAK MID LEVEL LOW APPEARS TO BE
CENTERED OVER CENTRAL CUBA WITH THE MODELS INITIALIZING THIS QUITE
WELL. LOOKING AT SURFACE STREAMLINE ANALYSIS, THERE ALSO APPEARS
TO BE A TROUGH JUST WEST OF THE CONVECTION OVER THE NORTH CENTRAL
CARIBBEAN. AS THE UPSTREAM TROUGH DIGS INTO THE NORTHEAST GULF OF
MEXICO, THE MID LEVEL LOW OVER CUBA WILL GET ABSORBED AND IT IS
THE SURFACE TROUGH THAT THE MODELS DEVELOP A CLOSED SURFACE LOW
FROM WITH THE NAM REMAINING THE FASTEST IN ITS DEVELOPMENT AND THE
ECMWF THE FARTHEST TO THE WEST. ONE THING IS NEARLY CERTAIN, NO
MATTER WHERE THE MID/SURFACE LOWS END UP BEING LOCATED, SOUTH
FLORIDA WILL HAVE AN INCREASE IN SHRA/TSRA ACTIVITY DUE TO THE
COLDER TEMPERATURES ALOFT AND AN INCREASE IN DEEP LAYER MOISTURE.
ANOTHER ISSUE IS THAT MET GUIDANCE HAS BEEN OUTPERFORMING MAV
GUIDANCE IN POPS FOR THE PAST FEW PERIODS. BUT CONSIDERING THE NAM
SEEMS TO BE DEVELOPING THE SYSTEM TOO QUICKLY, IS THIS TREND GOING
TO END WITH THIS CYCLE? ALL OF THIS BEING SAID, IT STILL REMAINS A
HIGHLY UNCERTAIN FORECAST ESPECIALLY FOR RAINFALL TOTALS NOT TO
MENTION THE LOCATION OF THE HIGHEST AMOUNTS. THE OTHER FACTOR IS
THE WIND DIRECTION. DEPENDING ON WHICH MODEL TURNS OUT MORE
CORRECT, THE GFS AND NAM FOR LATE TUESDAY AND TUESDAY NIGHT ARE
180 DEGREES APART JUST DUE TO THE FORECAST POSITION OF THE SURFACE
LOW. SO IT APPEARS AT THIS POINT THE BEST COURSE OF ACTION IS GO
STATUS QUO AND CONTINUE WITH THE HIGHER CHANCES FOR RAINFALL.

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

please keep re posting that periodically throughout the day as that is the best analysis by far with the system and seems dead on!!
also that analysis will hold till tomorrow when these features we are all waiting on will be showing themselves.