[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210610
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN AUG 21 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA... GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN
COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

FAR E ATLC WAVE IS ALONG 21W S OF 22N MOVING W 10-15 KT.  A 1011
MB LOW IS ALONG THE WAVE NEAR 13N.  THE LOW HAS CURVED BANDS ON
THE ITCZ WITH PLENTY OF CONVECTION.  THERE IS LITTLE SHEAR NEAR
THE SYSTEM AND SLOW DEVELOPMENT IS EXPECTED.  COMPUTER MODELS
STRONGLY SUGGEST THAT THIS WAVE HAS A CHANCE OF TURNING INTO A
TROPICAL CYCLONE DURING THE NEXT FEW DAYS.  SCATTERED MODERATE
TO ISOLATED STRONG CONVECTION IS FROM 13N-16N BETWEEN
19W-22W...AND FROM 6N-13N BETWEEN 22W-30W.

CENTRAL ATLC WAVE IS ALONG 43W/44W S OF 20N MOVING W 15-20 KT.
THIS IS A VERY BROAD WAVE. SURFACE OBSERVATIONS AND WATER VAPOR
LOOPS SHOW THAT THE WAVE HAS A DRIER THAN AVERAGE ENVIRONMENT
WITH DEWPOINTS A COUPLE DEGREES LESS THAN TYPICAL NEAR THE WAVE
AND STRONG SUBSIDENCE ALOFT DRYING OUT THE MID/UPPER LEVELS.
THE GFS FORECASTS THE WAVE TO GRADUALLY DIMINISH WITH TIME WITH
THE LARGE WAVE IN THE E ATLC AND A SURFACE TROUGH TO ITS WEST
BECOMING THE MORE DOMINANT FEATURES.  NO SIGNIFICANT
CONVECTION.

CENTRAL CARIBBEAN WAVE IS ALONG 69W S OF 23N MOVING W 15 KT.  A
LARGE AREA OF DISORGANIZED WIDELY SCATTERED CONVECTION IS N OF
PUERTO RICO FROM 18N-21N BETWEEN 65W-69W.  PUERTO RICO RADAR IS
SHOWING A MID-LEVEL ROTATION NEAR 20N67W WITH BANDS OF SHOWERS
AT LOWER-LEVELS CYCLONICALLY TURNING INTO THE CENTER.  THIS IS
CERTAINLY AN AREA TO WATCH FOR POTENTIAL TROPICAL CYCLONE
GENESIS DURING THE NEXT COUPLE OF DAYS WITH LIGHT SHEAR
FORECAST.

SW GULF WAVE IS ALONG 95W/96W S OF 21N THROUGH S MEXICO MOVING W
10-15 KT.  SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS
MOSTLY E OF THE WAVE AXIS OVER S MEXICO AND THE BAY OF CAMPECHE
FROM 14N-19N BETWEEN 87W-94W.  THIS WAVE COULD ENHANCE
CONVECTION OVER SE MEXICO S OF TAMPICO TOMORROW.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 14N17W 9N30W 10N43W 6N54W.  BESIDES
THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION...WIDELY
SCATTERED MODERATE CONVECTION IS FROM 3N-8N BETWEEN 30W-35W.

...DISCUSSION...

GULF OF MEXICO...
A 1018 MB HIGH IS LOCATED ALONG THE COAST OF LOUISIANA NEAR
29N91W.  WINDS ARE PREDOMINATELY LIGHT TO MODERATE...AND
EASTERLY S OF 26N.  CONVECTION HAS DISSIPATED OVER THE GULF
EXCEPT OVER THE BAY OF CAMPECHE AS DEPICTED IN THE TROPICAL WAVE
SECTION.  IN THE UPPER LEVELS...ANTICYCLONIC CIRCULATION IS OVER
S GEORGIA NEAR 32N83W.  40KT-50KT UPPER LEVEL EASTERLY WINDS
DOMINATES THE ENTIRE GULF.  EXPECT MORE CONVECTION IN THE BAY OF
CAMPECHE...AND OVER THE NORTH-CENTRAL GULF IN THE NEXT 24
HOURS.

CARIBBEAN SEA...
A TROPICAL WAVE IS OVER THE E CARIBBEAN...WHILE A 1006 MB LOW IS
INLAND OVER N COLOMBIA NEAR 8N74W.  MODERATE TRADEWINDS ARE OVER
THE CENTRAL CARIBBEAN S OF HISPANIOLA.  NUMEROUS STRONG
CONVECTION IS OVER PANAMA AND COSTA RICA S OF 10N.  PATCHES OF
SCATTERED MODERATE CONVECTION REMAIN OVER HISPANIOLA...JAMAICA
....AND CUBA.  IN THE UPPER LEVELS... NE FLOW IS OVER THE W
CARIBBEAN W OF 76W.  AN ANTICYCLONIC CIRCULATION IS N OF THE
LEEWARD ISLANDS NEAR 20N67W MAKING THE AREA MORE FAVORABLE FOR
TROPICAL DEVELOPMENT SINCE THE NORTHERN PORTION OF THE TROPICAL
WAVE IS BELOW AT THE SURFACE LEVEL.  EXPECT THE N AND W
CARIBBEAN TO HAVE THE GREATEST POTENTIAL FOR CONVECTION IS THE
NEXT 24 HOURS.

ATLANTIC OCEAN...
EASTERLY SURFACE FLOW DOMINATES THE ATLANTIC BETWEEN 20N-30N DUE
TO A 1033 MB HIGH N OF THE AZORES NEAR 41N23W.  A WEAK SURFACE
TROUGH IS OVER THE TROPICAL ATLANTIC ALONG 25N57W 13N55W
APPROACHING THE LEEWARD ISLANDS.  NO SIGNIFICANT CONVECTION IS
NOTED.  A LOW LEVEL SWIRL IS ALSO NOTED ALONG THE COAST OF NE
CUBA NEAR 21N75W...REMNANTS OF T.D. TEN.  IN THE UPPER LEVELS...
AN UPPER HIGH CENTERED OVER THE SE USA CONTROLS THE WEATHER W OF
75W N OF 25.. GENERALLY DRIER THAN AVERAGE.  FARTHER E.. AN
UPPER TROUGH LIES FROM 30N56W TO 24N68W.  A FEW SHOWERS ARE
BENEATH THE TROUGH AXIS THOUGH THEY ARE QUITE ISOLATED.  IN THE
CENTRAL ATLC..  A MID/UPPER LOW IS NEAR 28N45W AND IS MOVING
SLOWLY W WITH TROUGH AXIS SSW TO 20N51W.  THE GFS SUGGEST THE
FEATURE WILL MOVE OUT OF THE AREA WITH THE TROUGH RETREATING
FROM THE DEEP TROPICS. VERY DRY AIR ALOFT CONTINUES S OF THE LOW
N OF 10N BETWEEN 40W-60W AND E OF THE LOW N OF 15N W OF 30W.
OTHERWISE IN THE ATLC...  UPPER TROUGH EXTENDS FROM MADEIRA
ISLANDS TO 25N30W...BRINGING MID/UPPER MOISTURE TO WESTERN
SAHARA AND ASSISTING RARE TSTMS DEVELOPMENT.  UPPER HIGH IS JUST
N OF THE CAPE VERDES RIDGING WSW TO 15N55W WHERE IT MEETS A WEAK
INVERTED TROUGH SLIGHTLY E OF THE LESSER ANTILLES S OF 17N.  S
OF THE RIDGE AXIS... FAIRLY MOIST AIR IS PRESENT ALOFT WITH
STRONG SUBSIDENCE DRYING N OF THE AXIS.

$$
FORMOSA




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