[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON OCT 19 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 22W S OF 16N MOVING W NEAR 15 KT. THE
WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM ACROSS THE
EASTERN TROPICAL ATLC AS OBSERVED IN TOTAL PRECIPITABLE WATER
IMAGERY. GLOBAL MODEL GUIDANCE FIELDS OF 850 MB RELATIVE
VORTICITY AND 700 MB STREAMLINES ALSO DEPICT CYCLONIC TURNING IN
THE VICINITY OF THE WAVE AXIS BETWEEN 20W-27W. SCATTERED SHOWERS
AND ISOLATED MODERATE CONVECTION ARE FROM 7N-17N BETWEEN 18W-25W.

TROPICAL WAVE IS ALONG 36W S OF 13N MOVING W NEAR 12 KT. THE
WAVE COINCIDES WITH THE LEADING EDGE OF A DEEP LAYER MOISTURE
MAXIMUM OBSERVED ACROSS THE EASTERN TROPICAL ATLC E OF 40W IN
TOTAL PRECIPITABLE WATER IMAGERY. CIMSS WAVETRAK MODEL GUIDANCE
ALSO DEPICTS A MAXIMUM IN 850 MB RELATIVE VORTICITY FOCUSED WITH
THE NORTHERN EXTENT OF THE WAVE N OF 9N. SCATTERED SHOWERS AND
ISOLATED MODERATE CONVECTION ARE FROM 8N-15N BETWEEN 30W-39W.

TROPICAL WAVE IS ALONG 59W S OF 12N MOVING W NEAR 15 KT. AN AREA
OF DEEP LAYER MOISTURE APPEARS TO BE PROPAGATING WWD ACROSS
NORTHERN GUYANA AND EASTERN VENEZUELA AND PORTIONS OF THE
TROPICAL NORTH ATLC S OF 11N W OF 57W. SCATTERED SHOWERS AND
ISOLATED MODERATE CONVECTION ARE FROM 6N-11N BETWEEN 56W-62W.

TROPICAL WAVE IS ALONG 82W S OF 17N MOVING W NEAR 15 KT. THE
WAVE LIES WITHIN A BROAD AREA OF DEEP MOISTURE OVER THE WESTERN
CARIBBEAN AS OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. A
STATIONARY 1007 MB LOW IS IMMEDIATELY E OF THE WAVE AXIS
CENTERED NEAR 12N81W. UPPER LEVEL DIFFLUENCE LIES ALOFT IN THE
VICINITY OF THE WAVE AXIS AND IS ENHANCING NUMEROUS MODERATE AND
SCATTERED STRONG CONVECTION FROM 11N-18N BETWEEN 77W-84W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 15N17W 15N21W 12N23W 9N35W 9N37W
5N54W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE
SECTION...SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION ARE
FROM 8N-16N BETWEEN 24W-35W. SIMILAR CONVECTION IS ALONG THE W
AFRICA COAST FROM 8N-14N BETWEEN 12W-17W.

...DISCUSSION...

GULF OF MEXICO...
A 1027 MB SURFACE HIGH CENTERED OVER WESTERN MISSISSIPPI NEAR
33N91W EXTENDS A SURFACE RIDGE OVER FLORIDA...THE ENTIRE GULF OF
MEXICO AND EASTERN MEXICO. N-NE WINDS UP TO 25 KT DOMINATE OVER
THE GULF. THIS SURFACE HIGH IS SUPPORTED ALOFT BY THE BACKSIDE
OF AN UPPER LEVEL TROUGH WITH AXIS ALONG THE EASTERN U.S.
SEABOARD AND A PORTION OF THE WESTERN ATLC. NWLY WINDS ALOFT AND
VERY STRONG SUBSIDENCE IS OVER THE GULF N OF 22N. THE SURFACE
RIDGE IS FORECAST TO REMAIN IN PLACE ACROSS MUCH OF THE GULF
THROUGH MID-WEEK WITH SLY RETURN FLOW ACROSS THE WRN GULF BY
WEDNESDAY AHEAD OF THE NEXT COLD FRONT TO ENTER THE NW GULF
WATERS ON THURSDAY.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH IS OVER THE WESTERN ATLC AND GULF OF
MEXICO DIPPING SOUTH INTO THE NW CARIBBEAN. THIS UPPER LEVEL
TROUGHING SUPPORTS A COLD FRONT THAT EXTENDS INTO THE CARIBBEAN
SEA THROUGH THE WINDWARD PASSAGE AND CONTINUES ALONG 19N80W TO
THE NORTH CENTRAL HONDURAS COAST NEAR 16N86W. LOW-LEVEL
CONVERGENCE IN THE VICINITY OF THE FRONTAL BOUNDARY COUPLED WITH
UPPER LEVEL DIFFLUENCE E OF THE UPPER LEVEL TROUGH IS GENERATING
SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 120 NM EITHER SIDE
OF THE COLD FRONT. TO THE SOUTH OVER THE SW CARIBBEAN...THE
TROPICAL WAVE ALONG 82W AND A 1007 MB LOW CENTERED NEAR 12N81W
ARE PRODUCING NUMEROUS SHOWERS AND SCATTERED STRONG TSTMS FROM
11N-18N BETWEEN 77W-84W. UPPER LEVEL RIDGING POSITIONED ACROSS
THE SW CARIBBEAN W OF 70W IS ALSO ENHANCING THIS CONVECTION. E
OF 70W...UPPER LEVEL TROUGHING AND GENERALLY DRY NWLY FLOW ALOFT
ARE ACROSS THE EASTERN CARIBBEAN WITH ELY TRADE WINDS UP TO 20
KT. A FEW ISOLATED LOW-LEVEL SHOWERS ARE HOWEVER OCCURRING N OF
15N E OF 72W.

ATLANTIC OCEAN...
A COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N68W AND EXTENDS
S-SW TO THE WINDWARD PASSAGE NEAR 20N74W. SCATTERED SHOWERS AND
TSTMS ARE OCCURRING WITHIN 90 NM OF THE FRONT AND OVER THE SE
BAHAMAS INCLUDING THE SURROUNDING COASTAL WATERS FROM 21N-26N
BETWEEN 72W-77W. THIS FRONT IS SUPPORTED ALOFT BY A SHARP UPPER
LEVEL TROUGH W OF 70W WITH AXIS ALONG THE EASTERN U.S. SEABOARD
TO THE NW BAHAMAS AND WESTERN CUBA. A 1023 MB SURFACE HIGH IS
OVER THE CENTRAL ATLANTIC NEAR 34N47W. A WEAKNESS IN THE SUB-
TROPICAL RIDGE IS ANALYZED AS A SURFACE TROUGH THAT EXTENDS FROM
17N47W TO BEYOND 32N41W. LOW-LEVEL CONVERGENCE NEAR THE SURFACE
TROUGH IS GENERATING SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE
OF THE BOUNDARY. ANOTHER SURFACE TROUGH IS OVER THE EASTERN ATLC
ALONG 24N31W TO 30N27W. THESE TWO SURFACE FEATURES ARE SUPPORTED
ALOFT BY AN ELONGATED UPPER LEVEL LOW CENTERED NEAR 25N38W. THE
UPPER LOW STRETCHES NE TO BEYOND 32N24W AND SW TOWARDS THE
WINDWARD ISLANDS AND EXTREME EASTERN CARIBBEAN SEA NEAR 12N62W.

$$
HUFFMAN





This weather bulletin was brought to you by:
www.nashvilleweather.net