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

[gatorcane]

NWS Tampa on this Low. Interesting how it considers GFS and DGEX "much aggressive":

LONG TERM (FRIDAY NIGHT - WEDNESDAY)...DISCREPANCIES AND
INCONSISTENCIES BETWEEN MODELS CONTINUE IN THE LONG RANGE GUIDANCE
AS EACH SOLUTION HAS A DIFFERENT DEPICTION OF THE LOW DEVELOPMENT BY
MONDAY. GFS AND DGEX ARE VERY MUCH AGGRESSIVE WITH STRONG
CYCLOGENESIS TO THE SOUTH OF FLORIDA AND BRINGING IT INTO THE AREA
FOLLOWING VERY DIFFERENT PATHS. ECMWF CONTINUES TO BE THE MOST
CONSERVATIVE OF THE SOLUTIONS...WHICH BLENDED WITH CLIMO SHOULD
PROVIDE A BETTER FORECAST ALTERNATIVE AT THIS TIME. THIS WILL ALSO
BE IN BETTER AGREEMENT WITH SURROUNDING OFFICES. THANKS TO MFL AND
MLB FOR THE OFFICE COORDINATION.

http://www.srh.noaa.gov/tbw/getprodvers ... &version=1

NWS Miami on Low:

IN THE EXTENDED...THAT IS WHEN MODELS BEGIN TO DIVERGE
SIGNIFICANTLY. MODELS GENERALLY AGREE IN BRINGING CLOSE TO THE
AREA MOISTURE SURGE ACROSS PUERTO AND HISPANIOLA AT THIS TIME BY
LATE IN THE WEEK AND THE WEEKEND. WITH THAT PROBABILITY OF
PRECIPITATION SHOULD REMAIN IN THE 30% TO 40% RANGE THROUGH THE
WEEKEND. BEYOND THAT...SOLUTIONS RANGE FROM LOW LEVEL RIDGE TO THE
NORTH REMAINING IN PLACE PER THE ECMWF TO SOME SORT OF LOW
PRESSURE SYSTEM SOMEWHERE ACROSS THE FLORIDA PENINSULA. BUT THE
TREND IN THE GFS KEEPS FLIP-FLOPPING SO AT THIS TIME GIVEN CURRENT
SYNOPTIC PATTERN AND MORE STEADY SOLUTION OF THE ECMWF DECIDED TO
KEEP FORECAST AS IS FOR THE MOMENT FOR EARLY TO MIDDLE PART OF
NEXT WEEK. NEEDLESS TO SAY THE FORECAST IN THE EXTENDED PERIODS IS
VERY UNCERTAIN AT THIS TIME.

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

It's looking more and more likely like Florida will receive increased rain chances at least.

[Bailey1777]

When they say blended for a better forecast what would that forecast be?

[boca]

I think what their saying is the GFS is too aggressive on developing a system for this time of year.While the ECMWF is going with a weaker low if it develops at all. Tampa is just playing safe right now banking that we'll have just a weak trough around.

[gatorcane]

00Z GFS just in...all of those in Southern FL would welcome this low with all of that rain it seems it wants to bring in.

[boca]

I think that trough or tropical wave down by Puerto Rico might be the trigger to this low that the GFS is developing around Tues next week.Do you agree gatorcane?

[NDG]

NWS Tampa on this Low. Interesting how it considers GFS and DGEX "much aggressive":

LONG TERM (FRIDAY NIGHT - WEDNESDAY)...DISCREPANCIES AND
INCONSISTENCIES BETWEEN MODELS CONTINUE IN THE LONG RANGE GUIDANCE
AS EACH SOLUTION HAS A DIFFERENT DEPICTION OF THE LOW DEVELOPMENT BY
MONDAY. GFS AND DGEX ARE VERY MUCH AGGRESSIVE WITH STRONG
CYCLOGENESIS TO THE SOUTH OF FLORIDA AND BRINGING IT INTO THE AREA
FOLLOWING VERY DIFFERENT PATHS. ECMWF CONTINUES TO BE THE MOST
CONSERVATIVE OF THE SOLUTIONS...WHICH BLENDED WITH CLIMO SHOULD
PROVIDE A BETTER FORECAST ALTERNATIVE AT THIS TIME. THIS WILL ALSO
BE IN BETTER AGREEMENT WITH SURROUNDING OFFICES. THANKS TO MFL AND
MLB FOR THE OFFICE COORDINATION.

http://www.srh.noaa.gov/tbw/getprodvers ... &version=1

NWS Miami on Low:

IN THE EXTENDED...THAT IS WHEN MODELS BEGIN TO DIVERGE
SIGNIFICANTLY. MODELS GENERALLY AGREE IN BRINGING CLOSE TO THE
AREA MOISTURE SURGE ACROSS PUERTO AND HISPANIOLA AT THIS TIME BY
LATE IN THE WEEK AND THE WEEKEND. WITH THAT PROBABILITY OF
PRECIPITATION SHOULD REMAIN IN THE 30% TO 40% RANGE THROUGH THE
WEEKEND. BEYOND THAT...SOLUTIONS RANGE FROM LOW LEVEL RIDGE TO THE
NORTH REMAINING IN PLACE PER THE ECMWF TO SOME SORT OF LOW
PRESSURE SYSTEM SOMEWHERE ACROSS THE FLORIDA PENINSULA. BUT THE
TREND IN THE GFS KEEPS FLIP-FLOPPING SO AT THIS TIME GIVEN CURRENT
SYNOPTIC PATTERN AND MORE STEADY SOLUTION OF THE ECMWF DECIDED TO
KEEP FORECAST AS IS FOR THE MOMENT FOR EARLY TO MIDDLE PART OF
NEXT WEEK. NEEDLESS TO SAY THE FORECAST IN THE EXTENDED PERIODS IS
VERY UNCERTAIN AT THIS TIME.

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

It's looking more and more likely like Florida will receive increased rain chances at least.

Noticed that these AFDs from both Miami & Tampa were written before the 12z ECMWF had come out, like I had written at the FL thread, if 0z euro is close to its 12z run I am sure they will give some credibility to the gfs, though I think that a blend of them two is a sure bet in the timing of any low pressure development off of S FL late Sunday into early next week.

[NDG]

This mornings MLB AFD:
http://www.srh.noaa.gov/productview.php?pil=AFDMLB&max=10

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
335 AM EDT THU MAY 14 2009

MON-THU...THE GFS AND ECMWF INDICATE THAT SOUTHERN PORTION OF TROUGH
MOVING ACROSS THE SOUTHEAST STATES WILL CUT OFF OVER THE CENTRAL
TO SOUTHEAST GULF OF MEXICO. I AM NOT SO SURE THAT THE INITIAL
LOW THE GFS SHOWS MOVING NORTH MON-TUE FROM THE FLORIDA STRAITS TO
NORTHEAST FLORIDA WILL BE AS ORGANIZED INITIALLY AS THE MODEL
PROGS IT TO BE. WHATEVER HAPPENS AT THE SURFACE WILL TAKE SOME
MORE TIME TO PINPOINT. THE MAIN THING IS THAT IT LOOKS LIKE WE
WILL REMAIN ON THE MOIST SIDE OF THE DEVELOPING CUT OFF LOW. IF
THINGS WORK OUT AS PROGGED...SOME MUCH NEEDED WIDESPREAD RAINFALL
IS POSSIBLE.

WILL KEEP 30 PERCENT POPS THROUGH THE PERIOD BUT WOULD EXPECT
FUTURE FORECASTS TO BE ABLE TO INSERT HIGHER POPS ON A FEW DAYS

I agree with their thinking, that if any surface development takes place out of the cut off ULL, it will could take some time, so the Euro might have the right idea in the timing.

[KWT]

Will be interesting to watch, probably will remain extra-tropical but you never know, it could with enough time take on subtropical properties.

[ROCK]

http://wxmaps.org/pix/hurpot.html#ATL

[Ed Mahmoud]

Looking at the Euro, it shows a weak low with strongest winds removed to the Northeast. But still in the Gulf in 10 days.


I'm leaning, in my unprofessional and unofficial opinion, as a low wind rain-maker that is probably either non-tropical or barely sub-tropical, at best.

[gatorcane]

I think that trough or tropical wave down by Puerto Rico might be the trigger to this low that the GFS is developing around Tues next week.Do you agree gatorcane?

Yes I agree, you can see this tropical wave/trough-like feature over Haiti. That must be what the models are thinking will develop the low.

At this time I continue to think this will remain weak but has a decent chance of bringing much needed rainfall to Florida. There is still a chance the low develops and moves just east of Florida into the Bahamas, which would bring nearly no rain to Florida due to Florida being on the west side (dry side) of the system and the wind shear blowing off the activity to the east.

The strong high over the Western Atlantic is forecasted to get shunted eastward by a powerful short-wave early next week and depending upon the timing could be enough to eject the system NE east of FL. In fact that kind of setup is climatologically favored for May.

[Ed Mahmoud]

snipped from Houston/Galveston NWS

MON THROUGH WED FOR NEXT WEEK LOOKS TO BE RATHER QUIET. TEMPS
WILL BE SEASONABLE IF NOT JUST A DEGREE OR TWO BELOW CLIMO NORMS.
TEMPS DO REBOUND SOME WED INTO THU. THE MAIN UNCERTAINTY FOR NEXT WEEK IS IN REGARD TO THE UPPER LEVEL PATTERN. BOTH THE GFS AND ECMWF DEVELOP A CLOSED/CUTOFF UPPER LOW OVER THE C/E GULF. THE ECMWF FLOODS OUT FLORIDA TUE THROUGH FRI. THE GFS HOLDS ONTO THE LOW AS A MORE ELONGATED SHEAR AXIS OVER MUCH OF THE GULF. THE LOW TENDS TO MEANDER A BIT BUT WILL BE RESPONSIBLE FOR HELPING TO KEEP TEMPS NEAR NORMAL. BEING ON THE MORE SUBSIDENT SIDE OF THE TROUGH...WILL KEEP POPS OUT OF THE FORECAST...BUT SUSPECT THIS COULD CHANGE IF THE CENTER OF THE LOW EDGES BACK OVER TO THE WEST MID/LATE NEXT WEEK.

[gatorcane]

You can start to see now what the models are jumping on. If you look at that tropical wave/trough near Hispaniola (click the VIS loop link and ZOOM in), you see a distinct spin in the clouds as it moves W to WNW. Look at 22N, 74W, riding along the NE coast of Cuba...

http://www.ssd.noaa.gov/goes/east/watl/loop-vis.html

Also, the 12Z GFS is bringing a deluge of rain to Southern FL from the Southeast by day 4...as the low consolidates in the Straits of Florida. This is just what Southern FL needs to erase some major rainfall deficits.

However, the 12Z GFS is showing the Low moving to a position near the SE FL Coast and then it moves NE away from the coast. The possibility still exists if such a low forms it may not make it far enough West to really provide significant rainfall, however, it looks like a close call at the moment and I'm leaning towards a rainfall event, perhaps major, for Southern FL.

[Ed Mahmoud]

GFS doesn't seem to do much with that moisture until a mid/upper low cuts off from the main jet stream, which implies more of a baroclinically enhanced development.


One of Joe Bastardi's famous "hybrid howlers", gets some enhancement from warm water, but may or may not qualify as sub-tropical for NHC purposes.

(I love 4 panels...)



ETA:
By 180 hours, GFS develops another week low in the Gulf, and stacks the cold low over the surface low. Not tropical at all, but low shear. Kind of thing that could eventually evolve tropically.

Oh, and the hybrid howler may never get named, but it looks like some gale action into the Carolinas with "landfall".

[srainhoutx]

If anything develops, we'll need to see the Upper Low track NE and leave a surface LP behind in the GOM. Just a bit too soon IMHO, but stalled boundries have spawned "Tropical Action" in the past. Something to get us warmed up for "season".

[cycloneye]

The NAM model at 84 hours starts to show plenty of moisture in South Florida.

[cycloneye]

12z CMC moves the low westward into the EGOM.



http://moe.met.fsu.edu/cgi-bin/cmctc2.c ... =Animation

[gatorcane]

The 12Z GFS also brings it back west but weaker and at a more northern lattitude. It's becoming clear these models are responding to a building ridge behind the front that will block and ejection NE and out to sea:

http://moe.met.fsu.edu/cgi-bin/gfstc2.c ... =Animation

[cycloneye]

Look above your post.

[gatorcane]

:uarrow: Look above your post.

You beat me too it I edited my post but noted the GFS is similar to the CMC...