[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 142323
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SUN JUN 14 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
2245 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS ALONG 71W S OF 19N MOVING W AROUND 15 KT. THIS
WAVE COINCIDES WITH A RELATIVELY HIGHLY-AMPLIFIED MAXIMUM IN DEEP
LAYER MOISTURE BASED ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM
CIMSS. SURFACE OBSERVATIONS OVER THE DOMINICAN REPUBLIC AND COMPUTER
MODEL GUIDANCE INDICATE CYCLONIC CURVATURE IN THE LOW LEVEL FLOW
ACROSS THIS WAVE. SCATTERED MODERATE TO STRONG CONVECTION IS FROM
9N-12N BETWEEN 68W-71W INCLUDING PORTIONS OF NW VENEZUELA. SCATTERED
MODERATE CONVECTION IS FROM 18N-19N BETWEEN 69W-71W INCLUDING
PORTIONS OF HISPANIOLA.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 12N16W 7N22W 3N30W 2N40W 2N51W.
SCATTERED MODERATE CONVECTION IS FROM 4N-11N BETWEEN 19W-24W.
SCATTERED MODERATE CONVECTION IS ALSO S OF 3N BETWEEN 36W-45W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYER DRY AIR AND SUBSIDENCE IN NORTHERLY FLOW ALOFT COVER MUCH
OF THE GULF REGION...WHERE GENERALLY FAIR WEATHER IS PRESENT. THE
SUBSIDENCE IS SUPPORTING A 1019 MB SURFACE HIGH OVER THE CENTRAL
GULF NEAR 28N88W. ANTICYCLONIC FLOW AROUND THE SURFACE HIGH IS
AFFECTING MUCH OF THE GULF...WITH SE WINDS OF 15 TO 20 KT OCCURRING
ACROSS PORTIONS OF THE W GULF IN RESPONSE TO A BROAD SURFACE TROUGH
OVER MEXICO AND THE SOUTHERN PLAINS OF THE UNITED STATES. LITTLE
CHANGE IN THIS OVERALL PATTERN IS EXPECTED ACROSS MUCH OF THE GULF
DURING THE NEXT FEW DAYS. HOWEVER...A SURFACE TROUGH IS FORECAST TO
MOVE WESTWARD ACROSS THE S GULF FOR TUESDAY AND WEDNESDAY...
ACCOMPANIED BY SCATTERED THUNDERSTORMS.

CARIBBEAN SEA...
AN UPPER LEVEL TROUGH IS OVER THE FAR NW CARIBBEAN WITH AN AXIS
EXTENDING FROM 22N85W TO 16N91W AND EXTENDING SOUTHWESTWARD INTO THE
E PACIFIC REGION. THIS UPPER LEVEL TROUGH IS ASSOCIATED WITH A
SURFACE TROUGH EXTENDING FROM THE E YUCATAN PENINSULA NEAR 21N87W TO
NW HONDURAS NEAR 16N88W. LOW LEVEL CONVERGENCE IS SUPPORTING
SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 120 NM EITHER SIDE OF THE
SURFACE TROUGH. TO THE E...A BROAD UPPER LEVEL RIDGE IS AFFECTING
MUCH OF THE CARIBBEAN...WHERE DEEP LAYER MOISTURE IS PRESENT. A
SECOND SURFACE TROUGH IS PRESENT OVER THE CARIBBEAN...AND EXTENDS
FROM S OF CUBA NEAR 21N79W TO 14N82W TO N PANAMA NEAR 9N82W. LOW
LEVEL CONVERGENCE NEAR THIS SECOND SURFACE TROUGH IS COMBINING WITH
THE DEEP LAYER MOISTURE TO RESULT IN SCATTERED SHOWERS AND
THUNDERSTORMS WITHIN 180 NM EITHER SIDE OF THE SECOND SURFACE
TROUGH. RECENT SURFACE OBSERVATIONS CONFIRM CYCLONIC CURVATURE IN
THE LOW LEVEL FLOW ACROSS THIS TROUGH. ADDITIONALLY...ATMOSPHERIC
INSTABILITY IS RESULTING IN SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS CUBA AND THE NEARBY COASTAL WATERS. FARTHER TO THE
E...SUBSIDENCE IN NW FLOW ALOFT IS INHIBITING DEEP CONVECTION ACROSS
MUCH OF THE E CARIBBEAN.

ATLANTIC OCEAN...
ATMOSPHERIC INSTABILITY ASSOCIATED WITH AN UPPER LEVEL TROUGH ACROSS
THE SW NORTH ATLC IS SUPPORTING SCATTERED SHOWERS AND THUNDERSTORMS
N OF 23N BETWEEN 68W-78W...WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS N OF 21N BETWEEN 60W-67W. FARTHER TO THE
W...SUBSIDENCE IN DRY NORTHERLY FLOW ALOFT IS SUPPORTING GENERALLY
FAIR WEATHER ACROSS WESTERN PORTIONS OF THE SW NORTH ATLC.
HOWEVER...LOW LEVEL CONVERGENCE IS SUPPORTING INCREASED CLOUDINESS
AND ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF A SURFACE TROUGH
EXTENDING FROM 31N78W TO E OF THE FLORIDA PENINSULA NEAR 29N80W.
ACROSS THE CENTRAL AND E ATLC...GENERALLY FAIR WEATHER IS PRESENT
WHERE SUBSIDENCE IS OCCURRING NEAR A BROAD SURFACE RIDGE. THIS
SURFACE RIDGE IS ASSOCIATED WITH A 1024 MB SURFACE HIGH NEAR 30N53W.
HOWEVER...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM 17N54W TO AN UPPER
LEVEL LOW NEAR 19N52W TO A SECOND UPPER LEVEL LOW NEAR 26N47W TO
28N43W. THE NORTHERN UPPER LEVEL LOW IS ASSOCIATED WITH A 1020 MB
SURFACE LOW NEAR 30N46W. THESE FEATURES ARE SUPPORTING SCATTERED
SHOWERS FROM 17N-22N BETWEEN 46W-53W AND N OF 27N BETWEEN 43W-49W.
ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS PRESENT WITH
AN AXIS EXTENDING FROM 15N17W TO AN UPPER LEVEL HIGH NEAR 14N25W TO
7N44W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THESE FEATURES IS
SUPPORTING THE CONVECTION ASSOCIATED WITH THE ITCZ...AS WELL AS
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FROM 6N-10N BETWEEN
12W-15W.

$$
COHEN




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