[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 030005
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 02 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 2315 UTC.

...TROPICAL WAVES...

A LARGE ATLANTIC OCEAN TROPICAL WAVE IS ALONG 31W TO THE SOUTH
OF 18N MOVING WESTWARD 20 KT. THIS WAVE IS BROAD WITH THE LAST
VISIBLE SATELLITE IMAGES OF THE DAY TODAY INDICATING AN AREA OF
CYCLONIC TURNING COVERING THE AREA FROM 10N TO 20N BETWEEN 28W
AND 40W. THE WAVE POSITION IS ROUGHLY IN THE CENTER OF THE
CYCLONIC ENVELOPE WHERE CLOUD DRIFT WINDS SUGGEST A VORTICITY
MAXIMUM NEAR 10N31W. SYNOPTIC PRESSURE OBSERVATIONS FROM THE
CAPE VERDE ISLANDS SHOW A 3 MB PRESSURE INCREASE DURING AT LEAST
THE LAST 24 HOURS. QUIKSCAT DATA REVEAL NORTHEASTERLY 20 KT TO
25 KT WIND SPEEDS TO THE WEST OF THE WAVE TO THE NORTH OF 14N
DUE TO THE TIGHTENED PRESSURE GRADIENT BETWEEN THE WAVE AND THE
SUBTROPICAL RIDGE. DEEP CONVECTIVE PRECIPITATION REALLY DOES NOT
ACCOMPANY THIS WAVE. ITCZ PRECIPITATION IS BETWEEN 30W AND 40W
TO THE SOUTH OF THE WAVE.

AN ATLANTIC OCEAN TROPICAL WAVE HAS BEEN ADJUSTED W TO ALONG
50W/51W TO THE SOUTH OF 16N MOVING WESTWARD 15 TO 20 KT. THE
INTERACTION WITH AN UPPER LEVEL CYCLONIC CIRCULATION CENTER
TO ITS WEST IS GIVING ENERGY TO ISOLATED MODERATE SHOWERS
FROM 6N TO 11N BETWEEN 52W AND 58W.

A CARIBBEAN SEA TROPICAL WAVE IS ALONG 72W/73W TO THE SOUTH
OF 17N MOVING WEST 15 TO 20 KT. NO DEEP LAYER CONVECTIVE
PRECIPITATION ACCOMPANIES THIS WAVE. THIS WAVE IS MOVING TOWARD
THE AREA THAT IS IMMEDIATELY TO THE EAST OF THE 20N83W CARIBBEAN
SEA UPPER LEVEL CYCLONIC CIRCULATION CENTER.

...THE ITCZ...

FROM AFRICA NEAR 13N17W TO 12N27W TO 9N34W TO 6N49W...INTO
SURINAME NEAR 5N57W. SCATTERED MODERATE TO STRONG SHOWERS AND
THUNDERSTORMS FROM 5N TO 7N BETWEEN 37W AND 39W. ISOLATED
MODERATE
SHOWERS FROM 7N TO 10N BETWEEN AFRICA AND 20W...AND ELSEWHERE
FROM 3N TO 8N BETWEEN 30W AND 45W.

...DISCUSSION...

THE GULF OF MEXICO AND THE CARIBBEAN SEA WITH A 20N83W
CYCLONIC CIRCULATION CENTER...
SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 25N TO 28N BETWEEN
FLORIDA AND 92W. THIS PRECIPITATION IS IN THE MIDDLE OF CYCLONIC
FLOW TO THE NORTH WITH AN EASTERN U.S.A. DEEP LAYER TROUGH AND
UPPER LEVEL CYCLONIC FLOW THAT IS MOVING AROUND THE 20N83W
NORTHWESTERN CARIBBEAN SEA CYCLONIC CIRCULATION CENTER. SHOWERS
AND POSSIBLE THUNDERSTORMS ARE OCCURRING IN CUBA FROM EAST TO
WEST AROUND THE UPPER LEVEL CYCLONIC CENTER. SHOWERS AND
THUNDERSTORMS ARE LINED UP ALONG THE SIERRA MADRE OCCIDENTAL
FROM 23N TO 30N...WITH AN INTERIOR MEXICO 25N104W MIDDLE LEVEL
TO UPPER LEVEL CYCLONIC CENTER. SHOWERS AND THUNDERSTORMS ARE
IN CENTRAL AMERICA FROM THE WESTERN HALF OF HONDURAS TO GUATEMALA
AND MEXICO FROM THE WESTERN YUCATAN PENINSULA TO THE ISTHMUS OF
TEHUANTEPEC...ON THE WESTERN SIDE OF THE CYCLONIC FLOW THAT
IS MOVING AROUND THE 20N83W CYCLONIC CENTER THAT IS TO THE SOUTH
OF CUBA. STRONG SHOWERS AND THUNDERSTORMS ARE IN THE
SOUTHWESTERN CORNER OF THE CARIBBEAN SEA...TO THE NORTH OF
PANAMA AND REACHING EASTERN COASTAL NICARAGUA. BROAD MIDDLE LEVEL
TO UPPER LEVEL CYCLONIC FLOW IS IN THE SOUTHWESTERN CORNER OF
THE CARIBBEAN SEA HELPING TO ENERGIZE THIS PRECIPITATION. IT DOES
NOT HURT THAT THE 20N83W CYCLONIC CENTER IS TO THE NORTH WITH
ITS OWN CIRCULATION.

THE ATLANTIC OCEAN...
ATMOSPHERIC LIFT IN SOUTHWESTERLY FLOW ALOFT IS INTERACTING WITH
DEEP LAYER MOISTURE IN ORDER TO SUPPORT SCATTERED SHOWERS AND
THUNDERSTORMS THAT ARE TO THE WEST OF 31N72W 26N79W...INCLUDING
IN THE NW BAHAMAS. DEEP LAYER MOISTURE STREAMING AROUND AN UPPER
LEVEL HIGH CENTERED NEAR 27N70W IS SUPPORTING SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS N OF 27N BETWEEN 40W AND 50W.
AN UPPER LEVEL TROUGH AXIS EXTENDS FROM AN UPPER LEVEL LOW NEAR
31N37W TO 22N42W. A BROAD AREA OF LOW/MID-LEVEL DRY SAHARAN AIR
COVERS THE E ATLC S OF 25N TO THE ITCZ E OF 55W AND IS LIMITING
THE AREAL COVERAGE OF DEEP CONVECTION IN THIS AREA.

$$
MT



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