[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291042
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED JUL 29 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 27W S OF 22N MOVING W NEAR 15 KT. THIS
WAVE IS EMBEDDED WITHIN A VERY BROAD LOW/MID LEVEL CYCLONIC
CIRCULATION WITH A WEAK 1012 MB LOW W OF THE CAPE VERDE ISLANDS
CENTERED NEAR 14N31W. THIS WAVE IS ALSO AT THE LEADING EDGE OF A
DEEP LAYER MOISTURE MAXIMUM AS INDICATED BY TOTAL PRECIPITABLE
WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 8N-12N
BETWEEN 26W-32W.

A TROPICAL WAVE IS ALONG 56W S OF 18N MOVING W NEAR 18 KT. THIS
WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON
THE TOTAL PRECIPITABLE WATER PRODUCT. SCATTERED SHOWERS ARE FROM
10N-15N BETWEEN 52W-59W.

A TROPICAL WAVE IS ALONG 83W S OF 20N MOVING W NEAR 23 KT. A
MAXIMUM IN TOTAL PRECIPITABLE WATER IS ACROSS THE WRN CARIBBEAN
IN ASSOCIATION WITH THE WAVE. HOWEVER...DUE TO THE DRY AND
STABLE MIDDLE TO UPPER LEVEL AIR THAT COVERS MUCH OF THE
CARIBBEAN...NO SIGNIFICANT DEEP CONVECTION ACCOMPANIES THE WAVE
E OF WAVE AXIS. SCATTERED SHOWERS ARE INLAND ACROSS CENTRAL
AMERICA S OF 15N W OF THE WAVE AXIS.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 13N17W 13N26W 10N34W 10N54W AND
CONTINUING ACROSS NRN VENEZUELA ALONG 9N. SCATTERED MODERATE
CONVECTION IS FROM 9N-17N BETWEEN 16W-23W. SIMILAR CONVECTION
IS FROM 9N-11N BETWEEN 34W-42W.

...DISCUSSION...

GULF OF MEXICO...
A BENIGN UPPER LOW IS CENTERED INLAND OVER E/CENTRAL MEXICO W OF
TAMPICO GENERATING ISOLATED SHOWERS OVER THE BAY OF CAMPECHE S
OF 21N. AN UPPER LEVEL TROUGH IS OVER THE NE GULF WITH AN AXIS
EXTENDING FROM THE WRN FLORIDA PANHANDLE TO 27N90W. ATMOSPHERIC
LIFT IN MOIST W-SWLY FLOW ALOFT OVER THE NE GULF COMBINED WITH
THE ATMOSPHERIC INSTABILITY TO THE E OF THE UPPER LEVEL TROUGH
AXIS ARE SUPPORTING ISOLATED SHOWERS N OF 28N AND INLAND OVER
THE FLORIDA PANHANDLE. UPPER LEVEL DIFFLUENCE LOCATED ON THE
SERN QUADRANT OF AN UPPER LEVEL HIGH OVER THE ERN GULF CENTERED
NEAR 25N89W IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS
FROM 23N-27N E OF 85W. ELSEWHERE ACROSS THE GULF...A SURFACE
RIDGE OF HIGH PRESSURE EXTENDS ALONG 27N TO 93W AND IS EXPECTED
TO REMAIN IN PLACE OVER THE NEXT COUPLE OF DAYS PROVIDING
GENERALLY FAIR WEATHER AND SELY SURFACE WINDS ACROSS MUCH OF THE
GULF.

CARIBBEAN SEA...
UPPER LEVEL RIDGING DOMINATES ACROSS THE CARIBBEAN PROVIDING DRY
AIR AND MOSTLY STABLE CONDITIONS ALOFT. HOWEVER...WITH THE
TROPICAL WAVE ALONG 83W AND AN UPPER LEVEL RIDGE ACROSS SRN
PORTIONS OF CENTRAL AMERICA...SCATTERED SHOWERS AND ISOLATED
TSTMS ARE ACROSS THE GULF OF HONDURAS S OF 18N TO INLAND OVER
BELIZE...ERN GUATEMALA...HONDURAS AND NICARAGUA BETWEEN 83W-90W.
ACROSS MUCH OF THE CENTRAL AND E CARIBBEAN...THE DEEP LAYER DRY
AIR IS SUPPORTING MOSTLY FAIR WEATHER WITH FRESH TO STRONG ELY
TRADE WINDS E OF 82W. HOWEVER...A FEW ISOLATED FAST MOVING
SHOWERS ARE OBSERVED ON SATELLITE IMAGERY S OF 16N AND OVER THE
WINDWARD ISLANDS. AS THE TROPICAL WAVE ALONG 56W APPROACHES THE
LESSER ANTILLES OVER THE NEXT 24-36 HOURS...EXPECT INCREASED
CLOUDINESS AND SCATTERED SHOWER ACTIVITY WITH THE PASSAGE OF THE
WAVE.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS N OF 25N BETWEEN 73W-78W OVER THE SW
NORTH ATLC WATERS THAT IS GENERATING ISOLATED SHOWERS AND TSTMS
FROM 24N-29N BETWEEN 76W-81W. THE REMAINDER OF THE CENTRAL AND E
ATLC ARE DOMINATED BY DRY STABLE AIR AND FAIR WEATHER DUE TO A
SURFACE RIDGE ANCHORED BY A 1028 MB HIGH CENTERED NEAR 33N56W.

$$
HUFFMAN





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