Thread: Invest 90L near Cuba

All the models are saying there will be a low in the gulf next week and may bring a great deal of rain to Florida. Not a lot of wind is expected but could cause severe storms with hail because of the instability . Whatever happens it will be reported here

Tomorrow, Monday, our high temp here in Gainesville is only forecast to be 73 instead of the 90 degree temps we have been having. Lots of rain predicted, too.

tropical weather discussion
nws tpc/national hurricane center miami fl
805 pm edt sun may 17 2009

tropical weather discussion for north america...central
america...gulf of mexico...caribbean sea...northern sections
of south america...and atlantic ocean to the african coast
from the equator to 32n. The following information is based
on satellite imagery...meteorological analysis...weather
observations...and radar.

Based on 1800 utc surface analysis and satellite imagery
through 2245 utc.

...discussion...

Gulf of mexico...
A deep layer trough over the south central conus is associated
with a surface stationary front over the w gulf that extends
from south central louisiana near 29n91w to 26n95w to the coast
of mexico near 22n98w. Also...a surface trough is located to the
e of the front and extends from s mississippi near 30n89w to n
of the yucatan peninsula near 22n89w. Low level convergence near
the surface front and surface trough is supporting scattered
showers and isolated thunderstorms over the gulf n of 26n
between 86w-95w...with scattered showers s of 23n w of 91w.
Additionally...relatively unstable atmospheric conditions
associated with moist southeasterly flow over the e gulf are
supporting scattered showers and thunderstorms from 23n to 29n e
of 84w including the w florida peninsula...the florida
keys...the straits of florida...and w cuba. All of the shower
and thunderstorm activity is being enhanced by upper level
diffluence between the aforementioned deep trough and an upper
level ridge over the sw gulf. The front is expected to move
southeastward as a cold front through tuesday. Also... During
the next day...many of the global models are showing low
pressure developing over the n central caribbean...either
extratropical or subtropical...and moving generally n. The
development and track of the low remain uncertain...though
computer models suggest that winds will increase around the low.

Caribbean sea...
Numerous showers and thunderstorms are affecting portions of the
north central caribbean n of 16n between 71w-79w...including
jamaica...e cuba...and w hispaniola. This activity is being
supported by low level convergence near a surface trough that
extends from e cuba near 20n76w to 16n76w. The activity is also
being supported by upper level diffluence between an upper ridge
over the sw north atlc and an upper trough over the s caribbean.
During the next day...a surface low is forecast to develop along
the surface trough and move n of the caribbean monday night.

$$
cohen

450
fxus62 kmfl 180855
afdmfl

area forecast discussion
national weather service miami fl
455 am edt mon may 18 2009

discussion
a fairly impressive late season cold front currently
stretches from the central gulf of mexico, across the fl
panhandle, and then northeastward along the coast of the
carolinas. The inverted trough that past s fl a few nights ago
remains stretched across the west gulf while another trough
remains across western cuba. In the mid and upper levels... A
vigorous short wave continues to carve into the gulf while a mid
level low is pushing n-nw across west cuba.

The aforementioned systems have set up a very complicated and
difficult forecast with plenty of variables... We'll start with the
cold front. The front is expected to move south through today and
enter the lake region late this afternoon... It may even continue
on this evening and make it to far south florida by midnight or a
little after before putting on the brakes. While the front moves into s
fl the short wave pushing into the gulf will provide plenty of
divergence aloft/large scale ascent to allow widespread shower and
thunderstorm activity. The only limiting factor will be the amount
of heating today is in question, so kept chance of thunder instead
of widespread or likely. Also... While this is ongoing deep
tropical moisture from the southeast will begin to filter into the
area as the mid level and surface trough over west cuba move nw.
All of this will combine to possibly produce heavy rainfall
especially around the frontal boundary where the best lift will be
found. An isold severe tsra also can not be ruled out this
afternoon, especially if skies remain clear and temps warm into
the upper 80s to near 90 over the interior. Then as early as
tonight the forecast begins to become fuzzy... A weak low may
develop either from the trough near west cuba or from the cold
front/trough over the gulf combo. The gfs likes the trough near
cuba and lifts it through the bahamas, but then pushes it back to
s fl late in the week as the south end of the short wave cuts off
and retrogrades back west. The ecmwf and 6z nam tend to like the
western solution. If the gfs is correct then precip may be less or
at least delayed more than currently anticipated, but on the other
hand the nam and euro keep s fl wet for a while. The 0z nam and
ukmet also liked the trough over west cuba but took the low
across the cwa... Which is basically in the middle of all the
solutions... So stuck with the middle... And so has tafb...
However it should be noted that confidence is very low on the
evolution/track of this system and a deviation of just 100 miles
will mean widespread rain or isold shra for the area tuesday and
tues night and into wednesday. By the end of week and into the weekend
trended the forecast down to climo values as the surface low
supposedly lifts out.

Weatherspeak for "we don't know what the hell is going to happen"

If the gfs is correct then precip may be less or
at least delayed more than currently anticipated, but on the other
hand the nam and euro keep s fl wet for a while. The 0z nam and
ukmet also liked the trough over west cuba but took the low
across the cwa... Which is basically in the middle of all the
solutions... So stuck with the middle... And so has tafb...
However it should be noted that confidence is very low on the
evolution/track of this system and a deviation of just 100 miles
will mean widespread rain or isold shra for the area tuesday and
tues night and into wednesday.

Here's what Dr. Jeff Masters has to say about it:

A concentrated area of heavy thunderstorms has developed near Jamaica and eastern Cuba, in association with a mid- to upper-level trough of low pressure. The latest runs of the . . . global dynamical computer models continue to forecast that this disturbance will develop into an extratropical low by Tuesday. The low should bring heavy rain and possible flooding problems to Cuba, Florida, and the Bahamas this week as it lifts northwestward over Florida. Up to eight inches of rain may fall over Florida by Friday . . .

He goes on to say that there's too much shear over Cuba for it to develop into a tropical or even subtropical stiorm, BUT, if it heads into the GOM, there's slight chance (10%) that it could get to subtropial storm status.

Atlantic Basin Tropical Discussion

Atlantic | East Pacific

000AXNT20 KNHC 181743TWDAT TROPICAL WEATHER DISCUSSIONNWS TPC/NATIONAL HURRICANE CENTER MIAMI FL205 PM EDT MON MAY 18 2009TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONSOF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COASTFROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASEDON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHEROBSERVATIONS...AND RADAR.BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC....TROPICAL WAVES...A TROPICAL WAVE IS ALONG 44W/45W S OF 12N TO 3N MOVING W NEAR 10 KT. THIS WAVE IS EMBEDDED WITHIN BROAD SURFACE CYCLONIC FLOW WITH VISIBLE IMAGERY SHOWING AN INVERTED-V CLOUD PRESENTATION IN THE LOW-LEVEL CLOUD FIELD S OF 6N BETWEEN 42W-47W. AN EARLIER ASCAT PASS AROUND 1200 UTC SHOWED 15-20 KT WINDS IN THE VICINITY OF THE WAVE AXIS WITH ISOLATED MODERATE CONVECTION FROM 1N-5N BETWEEN 43W-47W....ITCZ...THE ITCZ AXIS IS CENTERED ALONG 5N10W 1N20W CROSSING THE EQUATOR NEAR 24W EXTENDING TO 2S38W AND INTO NE BRAZIL NEAR 1S46W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-6N BETWEEN 10W-17W. SIMILAR CONVECTION IS S OF 5N BETWEEN 19W-26W....DISCUSSION...GULF OF MEXICO...A DEEP LAYER TROUGH OVER THE ERN CONUS IS ASSOCIATED WITH A SURFACE STATIONARY FRONT OVER THE FLORIDA PENINSULA AND E GULF THAT AT 1500 UTC EXTENDS FROM TITUSVILLE FLORIDA TO TAMPA BAY AND ALONG 27N86W 24N89W CLIPPING THE NW YUCATAN PENINSULA AND ALONG THE COAST TO 19N92W. ALSO...A SURFACE TROUGH IS LOCATED TO THE E OF THE FRONT AND EXTENDS FROM NEAR 28N84W TO 22N85W. LOW LEVEL CONVERGENCE NEAR THE STATIONARY FRONT AND SURFACE TROUGH IS SUPPORTING NUMEROUS SHOWERS AND SCATTERED TSTMS OVER THE GULF N OF 24N E OF 88W TO OVER THE FLORIDA PENINSULA AND INTO THE W ATLC. THIS ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN THE AFOREMENTIONED DEEP TROUGH AND AN UPPER LEVEL RIDGE OVER THE SW GULF. THE FRONT IS EXPECTED TO GRADUALLY WEAKEN ACROSS THE GULF DURING THE NEXT DAY...AS MANY OF THE GLOBAL MODELS ARE SHOWING LOW PRESSURE DEVELOPING OVER THE SW NORTH ATLC AND SE GULF...EITHER EXTRATROPICAL OR SUBTROPICAL...AND MOVE GENERALLY N. THE DEVELOPMENT AND TRACK OF THE LOW REMAINS UNCERTAIN...THOUGH COMPUTER MODELS SUGGEST THAT WINDS WILL INCREASE AROUND THE LOW.CARIBBEAN SEA...SCATTERED SHOWERS AND TSTMS ARE AFFECTING PORTIONS OF THE NORTH CENTRAL CARIBBEAN N OF 15N BETWEEN 68W-77W...INCLUDING E CUBA... HISPANIOLA AND THE WINDWARD PASSAGE. THIS ACTIVITY IS BEING SUPPORTED BY LOW LEVEL CONVERGENCE NEAR A SURFACE TROUGH THAT EXTENDS FROM EXUMA SOUND IN THE BAHAMAS ACROSS ERN CUBA TO 16N76W. THE ACTIVITY IS ALSO BEING SUPPORTED BY MIDDLE TO UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER RIDGE OVER THE SW NORTH ATLC AND AN UPPER TROUGH OVER THE CENTRAL CARIBBEAN. DURING THE NEXT DAY...A SURFACE LOW IS FORECAST TO DEVELOP ALONG THE SURFACE TROUGH AND MOVE N OF THE CARIBBEAN BY TUESDAY. UPPER LEVEL DIVERGENCE AND ATMOSPHERIC INSTABILITY ASSOCIATED WITH THE UPPER TROUGH OVER THE CENTRAL CARIBBEAN IS ALSO SUPPORTING SCATTERED SHOWERS OVER THE NE CARIBBEAN N OF 16N...IMPACTING PUERTO RICO...THE VIRGIN AND LEEWARD ISLANDS.ATLANTIC OCEAN...AN OCCLUDED 1009 MB SURFACE LOW IS QUASI-STATIONARY NEAR 32N52W. AN ASSOCIATED SURFACE STATIONARY FRONT EXTENDS FROM 30N45W TO 25N46W TO 22N50W W-SW TO NEAR BARBUDA. LOW-LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS ALONG AND WITHIN 250 NM E OF THE SURFACE FRONT N OF 22N. S OF 22N...SCATTERED SHOWERS ARE WITHIN 60 NM EITHER SIDE OF THE FRONT. A SURFACE TROUGH IS ALSO ANALYZED TO THE W OF THE STATIONARY FRONT AND EXTENDS FROM 31N49W TO 28N49W TO 24N57W. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 30 NM EITHER SIDE OF THIS SURFACE TROUGH. ALL OF THIS SHOWER AND THUNDERSTORM ACTIVITY IS BEING ENHANCED BY UPPER LEVEL DIFFLUENCE IN THE ERN SEMICIRCLE OF AN UPPER LOW NEAR 32N52W. FARTHER TO THE W...A SURFACE RIDGE EXTENDS SW FROM A SURFACE HIGH PRESSURE CENTERED NW OF BERMUDA. SUBSIDENCE AND ATMOSPHERIC STABILITY ASSOCIATED WITH AN UPPER RIDGE OVER THE SW NORTH ATLC...IS SUPPORTING GENERALLY FAIR WEATHER CONDITIONS BETWEEN 57W-73W. HOWEVER...MOIST SELY LOW LEVEL FLOW OVER PORTIONS OF THE SW NORTH ATLC IS SUPPORTING SCATTERED SHOWERS AND TSTMS W OF 72W ALL FOCUSED ON A STATIONARY FRONT THAT ENTERS THE REGION NEAR 32N77W EXTENDING SW TO NEAR TITUSVILLE FLORIDA. ADDITIONALLY...SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH THE SURFACE TROUGH OVER THE CENTRAL CARIBBEAN ACROSS ERN CUBA TO 23N76W ARE MOVING NWD INTO THE W ATLC IMPACTING THE WINDWARD PASSAGE...TURKS AND CAICOS ISLANDS AS WELL AS THE BAHAMAS. DURING THE NEXT DAY...MANY OF THE GLOBAL MODELS ARE SHOWING LOW PRESSURE DEVELOPING OVER THE SW NORTH ATLC AND SE GULF OF MEXICO...EITHER EXTRATROPICAL OR SUBTROPICAL...AND MOVING GENERALLY NWD. THE PRESSURE GRADIENT AROUND THE LOW IS FORECAST TO RESULT IN GALE CONDITIONS N OF 29N W OF 76W EARLY TUESDAY THROUGH WEDNESDAY. ACROSS THE E ATLC...A SURFACE RIDGE IS PRESENT WHERE MAINLY ZONAL FLOW ALOFT IS OBSERVED AND FAIR WEATHER CONDITIONS PERSIST. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS PRESENT S OF 12N E OF 58W WITH UPPER LEVEL HIGHS CENTERED NEAR 6N26W AND 5N48W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL HIGHS AND RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.$$HUFFMAN

ZCZC MIATWOAT ALL
TTAA00 KNHC DDHHMM
SPECIAL TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
735 PM EDT MON MAY 18 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

1. SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT THERE HAS
BEEN LITTLE CHANGE WITH A WEAK SURFACE LOW LOCATED JUST TO THE
SOUTH OF THE CENTRAL BAHAMAS. SOME SLOW DEVELOPMENT OF THIS SYSTEM
IS POSSIBLE DURING THE NEXT DAY OR TWO AS IT MOVES GENERALLY
NORTHWARD AT 10 TO 15 MPH. AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT WILL INVESTIGATE THE SYSTEM ON TUESDAY...IF NECESSARY.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ANOTHER
SPECIAL OUTLOOK REGARDING THIS SYSTEM WILL BE ISSUED TUESDAY
MORNING.

$$
FORECASTER BLAKE

00
ABNT20 KNHC 182335
TWOAT
SPECIAL TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
735 PM EDT MON MAY 18 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT THERE HAS
BEEN LITTLE CHANGE WITH A WEAK SURFACE LOW LOCATED JUST TO THE
SOUTH OF THE CENTRAL BAHAMAS. SOME SLOW DEVELOPMENT OF THIS SYSTEM
IS POSSIBLE DURING THE NEXT DAY OR TWO AS IT MOVES GENERALLY
NORTHWARD AT 10 TO 15 MPH. AN AIR FORCE RESERVE HURRICANE HUNTER
AIRCRAFT WILL INVESTIGATE THE SYSTEM ON TUESDAY...IF NECESSARY.
THERE IS A LOW CHANCE...LESS THAN 30 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ANOTHER
SPECIAL OUTLOOK REGARDING THIS SYSTEM WILL BE ISSUED TUESDAY
MORNING.

$$
FORECASTER BLAKE

http://www.nhc.noaa.gov/text/refresh/MI ... 2335.shtml