[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 281736
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE JUL 28 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1645 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 22W S OF 24N MOVING W NEAR 10 KT. THIS
WAVE IS EMBEDDED WITHIN A VERY BROAD LOW/MID LEVEL CYCLONIC
ROTATION WITH A WEAKENING 1012 MB LOW SW OF THE CAPE VERDE
ISLANDS NEAR 15N27W AS INDICATED BY QUIKSCAT. THIS WAVE IS AT
THE LEADING EDGE OF A MOISTURE MAXIMUM AS INDICATED BY TOTAL
PRECIPITABLE WATER IMAGERY. ANY CONVECTION IS ASSOCIATED WITH
THE ITCZ.

A TROPICAL WAVE IS ALONG 49W/50W S OF 17N MOVING W 10-20 KT.
THIS WAVE COINCIDES WITH A APEX OF A MOISTURE MAXIMUM BASED ON
THE TOTAL PRECIPITABLE WATER PRODUCT. SCATTERED SHOWERS ARE FROM
11N-15N BETWEEN 49W-53W.

A TROPICAL WAVE IS ALONG 75W/76W S OF 19N MOVING W NEAR 25 KT.
VISIBLE SATELLITE IMAGERY INDICATES A BROAD INVERTED V
CURVATURE THAT COVERS MOST OF THE CARIBBEAN. HOWEVER...DUE TO
DRY STABLE AIR THAT ALSO COVERS MUCH OF THE CARIBBEAN...NO
SHOWERS OR CONVECTION IS IN THE AREA.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 15N16W 11N24W 10N35W 11N50W INTO
SOUTH AMERICA NEAR 9N61W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 60 NM OF THE ITCZ FROM 29W-34W. CLUSTERS OF
SCATTERED MODERATE CONVECTION ARE FROM 9N-14N E OF 26W TO INLAND
OVER W AFRICA AND FROM 7N-10N BETWEEN 31W-40W.

...DISCUSSION...

GULF OF MEXICO...
A RATHER BENIGN UPPER LOW IS ALONG THE COAST OF MEXICO NEAR
TAMPICO GENERATING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 60 NM
ALONG THE COAST FROM TAMPICO TO LAGUNA MORALES. AN UPPER LEVEL
TROUGH IS OVER THE E GULF WITH AN AXIS EXTENDING ACROSS THE
FLORIDA PENINSULA TO 23N82W AND CONTINUING W TO THE REMNANTS OF
AN UPPER LEVEL LOW NEAR 26N89W. ATMOSPHERIC LIFT IN MOIST SWLY
FLOW ALOFT IS MOSTLY OVER THE W ATLC COMBINED WITH THE
ATMOSPHERIC INSTABILITY TO THE E OF THE UPPER LEVEL TROUGH AXIS
ARE SUPPORTING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE
FAR SE GULF FROM THE FLORIDA KEYS TO OVER CUBA E OF 83W THROUGH
THE STRAITS OF FLORIDA INTO THE W ATLC. ACROSS THE N GULF
WATERS...UPPER LEVEL MOISTURE STREAMING SE W OF THE UPPER LEVEL
RIDGE IS SUPPORTING ISOLATED SHOWERS MAINLY INLAND WITH A FEW
MOVING OVER THE IMMEDIATE COASTAL WATERS FROM PANAMA CITY
FLORIDA TO THE LOUISIANA/TEXAS BORDER. THE SURFACE RIDGE EXTENDS
FROM THE ATLC OVER THE E HALF OF THE GULF AND IS EXPECTED TO
CHANGE LITTLE OVER THE NEXT COUPLE OF DAYS.

CARIBBEAN SEA...
THE UPPER TROUGH OVER THE E GULF OF MEXICO IS DRAWING UPPER
LEVEL MOISTURE S ACROSS CUBA TO THE GULF OF HONDURAS GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS MAINLY N OF 19N FROM
76W-85W. ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN...DEEP LAYER
DRY AIR IS SUPPORTING MOSTLY FAIR WEATHER. FRESH TO STRONG
EASTERLY TRADE WINDS MAINLY E OF THE TROPICAL WAVE ARE
GENERATING ISOLATED FAST MOVING SHOWERS S OF 15N TO OVER THE
WINDWARD ISLANDS. SIMILARLY...THE LOW LEVEL CONVERGENT FLOW OVER
THE SW CARIBBEAN IS ENHANCING SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 12N-16N W OF 80W TO INLAND OVER NICARAGUA AND
THE FAR NE HONDURAS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH OVER THE E GULF OF MEXICO EXTENDS OVER THE
W ATLC W OF 76W AND COUPLED WITH AN UPPER RIDGE N OF THE TURKS
AND CAICOS IS PROVIDING UPPER DIFFLUENCE TO GENERATE SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS WITHIN 90/120 NM OF LINE FROM THE
FLORIDA COAST NEAR FORT LAUDERDALE TO BEYOND 32N75W AND S INTO
THE STRAITS OF FLORIDA. AN UPPER LEVEL LOW IS CENTERED IN THE
CENTRAL ATLC NEAR 30N55W GENERATING SCATTERED SHOWERS AND
POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60/75 NM OF LINE FROM
27N56W TO 30N54W. THE REMAINDER OF THE CENTRAL AND E ATLC ARE
DOMINATED BY DRY STABLE AIR AND THEREFORE UNDER FAIR WEATHER.
THE ENTIRE ATLC BASIN IS ALSO DOMINATED BY A SURFACE RIDGE
ANCHORED BY A 1027 MB HIGH NEAR 34N57W.

$$
WALLACE



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