[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 220516
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SAT NOV 22 2008

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
0445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS TILTED FROM 14N56W TO 7N58W TO S GUYANA AT
7N58W. THIS WAVE IS MOVING W NEAR 10 KT. CIMSS WAVETRAK PRODUCT
INDICATES A MAXIMUM IN LOW LEVEL CYCLONIC CIRCULATION IN THE
VICINITY OF THIS WAVE. ADDITIONALLY...A MAXIMUM IN DEEP LAYER
MOISTURE COINCIDES WITH THIS WAVE BASED ON TOTAL PRECIPITABLE
WATER PRODUCT FROM CIMSS. SCATTERED SHOWERS ARE OCCURRING WITHIN
120 NM EITHER SIDE OF THE WAVE AXIS N OF 9N.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 12N15W 10N22W 8N32W 7N42W 4N52W.
SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 18W-29W.

...DISCUSSION...

GULF OF MEXICO...
STRONG SW TO W UPPER LEVEL WINDS COVER THE GULF REGION IN THE
BASE OF A BROAD UPPER TROUGH OVER THE E CONUS AND W ATLC. THIS
UPPER TROUGH IS SUPPORTING A SURFACE FRONT THAT EXTENDS FROM
S FLORIDA NEAR 25N81W TO 25N89W TO A 1025 MB SURFACE LOW IN THE
W GULF NEAR 25N96W TO 21N97W AND EXTENDS WESTWARD OVER E MEXICO.
ALSO...A SURFACE TROUGH EXTENDS NORTHWARD FROM THE SURFACE LOW
TO 27N97W TO SE OF THE TEXAS COAST NEAR 28N96W. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM OF THE
SURFACE FRONT...LOW...AND TROUGH. TO THE N OF THESE FEATURES...A
COOLER AND DRIER AIRMASS...CHARACTERIZED AS A MODIFIED
CONTINENTAL POLAR AIRMASS...IS IN PLACE. THIS AIRMASS IS BEING
SUPPORTED BY A 1038 MB SURFACE HIGH OVER THE E CONUS...WITH AN
ASSOCIATED SURFACE RIDGE EXTENDING ACROSS THE N GULF. FREEZE
WARNINGS AND WIND CHILL ADVISORIES ARE IN EFFECT FOR TONIGHT
THROUGH SATURDAY MORNING FOR PORTIONS OF FLORIDA. AS COOLER AIR
IS BEING ADVECTED OVER THE RELATIVELY WARMER GULF WATERS...WEAK
LOW LEVEL INSTABILITY IS SUPPORTING SCATTERED STRATOCUMULUS
CLOUDS ACROSS THE GULF MAINLY FROM 25N-28N. HOWEVER...SUBSIDENCE
AND STABLE ATMOSPHERIC CONDITIONS HIGHER IN THE ATMOSPHERE ARE
INHIBITING DEEP CONVECTION ACROSS THE GULF REGION.
ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE BLOWING THROUGH
THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS IN THE
E PACIFIC REGION.

CARIBBEAN SEA...
IN THE SW CARIBBEAN...A 1009 MB SURFACE LOW IS LOCATED N OF
PANAMA NEAR 10N82W. ADDITIONALLY...A SURFACE STATIONARY FRONT
EXTENDS FROM THIS SURFACE LOW TO 16N76W TO E HISPANIOLA NEAR
19N68W. LOW LEVEL CONVERGENCE NEAR THE SURFACE LOW AND SURFACE
FRONT IS INTERACTING WITH DEEP LAYER MOISTURE OVER THE S
CARIBBEAN TO GENERATE SCATTERED SHOWERS AND THUNDERSTORMS OVER
THE CARIBBEAN S OF 15N W OF 76W. THIS ACTIVITY IS BEING ENHANCED
BY UPPER LEVEL DIVERGENCE IN THE VICINITY OF AN UPPER RIDGE
PRESENT OVER THE W CARIBBEAN...WITH THE AXIS OF THIS UPPER RIDGE
EXTENDING FROM N COLOMBIA NEAR 11N73W TO 17N81W TO THE
NW CARIBBEAN NEAR 21N85W. OVER THE E CARIBBEAN...UPPER LEVEL
DIVERGENCE IS INTERACTING WITH DEEP LAYER MOISTURE TO SUPPORT
SCATTERED SHOWERS AND THUNDERSTORMS S OF 15N E OF 69W.

ATLANTIC OCEAN...
A BROAD UPPER LEVEL TROUGH OVER THE E CONUS AND W ATLC IS
SUPPORTING A SURFACE COLD FRONT THAT EXTENDS FROM S FLORIDA NEAR
25N81W TO 29N73W TO 32N69W TO NE OF THE DISCUSSION AREA.
ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THIS
COLD FRONT. TO THE W OF THIS COLD FRONT...A MODIFIED CONTINENTAL
POLAR AIRMASS IS IN PLACE...WITH TEMPERATURES BELOW SEASONAL
AVERAGES ACROSS FLORIDA AND SCATTERED STRATOCUMULUS CLOUDS
BETWEEN THIS FRONT AND 79W. ALSO...A SURFACE STATIONARY FRONT
EXTENDS FROM E HISPANIOLA NEAR 19N68W TO 25N58W TO 32N50W...WITH
SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE STATIONARY
FRONT. OVER THE NEXT DAY...A 1017 MB SURFACE LOW IS FORECAST TO
FORM NEAR 28N55W. TO THE E...A SURFACE TROUGH EXTENDS FROM
28N50W TO 22N44W...WITH ANOTHER SURFACE TROUGH EXTENDING FROM
16N55W TO 14N49W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM
EITHER SIDE OF EACH OF THESE SURFACE TROUGHS. ALSO...AN UPPER
TROUGH IS PRESENT OVER THE E ATLC N OF 20N E OF 43W WITH AN
ASSOCIATED SURFACE TROUGH EXTENDING FROM A 1014 MB SURFACE LOW
NEAR 23N32W TO 20N32W TO 18N34W. LOW LEVEL CONVERGENCE NEAR THE
SURFACE TROUGH AND SURFACE LOW IS SUPPORTING SCATTERED SHOWERS
FROM 18N-25N BETWEEN 25W-33W...WHICH IS BEING ENHANCED BY UPPER
LEVEL DIVERGENCE ASSOCIATED WITH A MID/UPPER-LEVEL WIND SPEED
MAXIMUM.

$$
COHEN




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