[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191134
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED NOV 19 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 43W S OF 17N MOVING W 10-15 KT. THIS
TROPICAL WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM BASED
ON TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. ALSO...CIMSS
WAVETRAK PRODUCT INDICATES A MAXIMUM IN LOW LEVEL CYCLONIC
CIRCULATION ALONG THE WAVE AXIS. SCATTERED MODERATE CONVECTION
IS FROM 7N-15N BETWEEN 41W-49W.

A TROPICAL WAVE IS ALONG 73W/74W S OF 16N MOVING W 10-15 KT. A
MAXIMUM IN DEEP LAYER MOISTURE COINCIDES WITH THIS WAVE.
ALSO...UPPER AIR TIME-HEIGHT ANALYSIS FOR CURACAO...LOCATED IN
THE NETHERLANDS ANTILLES NEAR 12N69W...DEPICTS VEERING OF MEAN
LOW/MID-LEVEL FLOW FROM NE TO SE OVER THE LAST DAY SUGGESTING
WAVE PASSAGE. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM
EITHER SIDE OF THIS WAVE S OF 12N...INCLUDING PORTIONS OF N
COLOMBIA AND NW VENEZUELA.

...THE ITCZ...
THE ITCZ AXIS IS ANALYZED ALONG 9N12W 6N22W 6N36W 10N51W 8N60W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM
EITHER SIDE OF THE ITCZ AXIS BETWEEN 26W-34W. SCATTERED MODERATE
CONVECTION IS FROM 9N-14N BETWEEN 53W-60W.

...DISCUSSION...

GULF OF MEXICO...
STRONG WEST-NORTHWESTERLY FLOW ALOFT AND DEEP LAYER DRY AIR ARE
PRESENT OVER MUCH OF THE GULF REGION. ALSO...A MODIFIED
CONTINENTAL POLAR AIRMASS PERSISTS ACROSS THE GULF REGION. AS A
RESULT... TEMPERATURES ACROSS THE GULF REGION ARE BELOW SEASONAL
AVERAGES. THIS RELATIVELY COOLER AND DRIER AIRMASS IS BEING
REINFORCED BY A SURFACE COLD FRONT THAT EXTENDS FROM THE SE
TEXAS COAST NEAR 29N95W TO 24N85W TO S OF FLORIDA NEAR 24N82W.
WITH INCREASED N TO NE WINDS SUPPORTING LOW-LEVEL COLD AIR
ADVECTION IN THE WAKE OF THE COLD FRONT...FREEZE WARNINGS AND
WIND CHILL ADVISORIES ARE IN EFFECT FOR THIS MORNING...WITH
FREEZE WATCHES IN EFFECT FOR LATE TONIGHT THROUGH THURSDAY
MORNING...FOR PORTIONS OF FLORIDA. ALSO...A 1029 MB SURFACE HIGH
IS CENTERED OVER NE MEXICO NEAR 25N99W...WITH AN ASSOCIATED
SURFACE RIDGE EXTENDING INTO THE W GULF. AS THE COOLER AIR IS
BEING ADVECTED OVER THE RELATIVELY WARMER GULF WATERS...WEAK LOW
LEVEL INSTABILITY IS SUPPORTING SCATTERED STRATOCUMULUS CLOUDS
ACROSS THE GULF. HOWEVER...SUBSIDENCE AND STABLE ATMOSPHERIC
CONDITIONS HIGHER IN THE ATMOSPHERE ARE INHIBITING DEEP
CONVECTION ACROSS THE GULF REGION. ADDITIONALLY...STRONG
NORTHERLY SURFACE WINDS ARE BLOWING THROUGH THE ISTHMUS OF
TEHUANTEPEC RESULTING IN STORM FORCE WINDS IN THE E PACIFIC
REGION.

CARIBBEAN SEA...
ACROSS THE NW CARIBBEAN...A SURFACE STATIONARY FRONT EXTENDS
FROM W OF HAITI NEAR 20N74W TO 16N80W TO N COSTA RICA NEAR
11N85W. LOW LEVEL CONVERGENCE NEAR THIS FRONT IS INTERACTING
WITH DEEP MOISTURE OVER THE W CARIBBEAN TO GENERATE SCATTERED
SHOWERS AND THUNDERSTORMS S OF 17N W OF 73W. 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 15N79W TO
18N83W. THIS ACTIVITY IS ALSO BEING ENHANCED BY THE TROPICAL
WAVE ALONG 73W/74W. OVER THE E CARIBBEAN...AN UPPER LEVEL RIDGE
EXTENDS FROM N VENEZUELA NEAR 10N66W TO 16N64W TO 18N63W TO THE
SW ATLC...WITH UPPER LEVEL DIVERGENCE SUPPORTING SCATTERED
SHOWERS OVER THE E CARIBBEAN S OF 15N E OF 70W.

ATLANTIC OCEAN...
A VIGOROUS UPPER TROUGH IS OVER THE E CONUS AND THE W ATLC...
WHICH IS SUPPORTING A SURFACE STATIONARY FRONT AND TWO SURFACE
COLD FRONTS. THE STATIONARY FRONT EXTENDS FROM W OF HAITI NEAR
20N74W TO 27N64W TO 31N61W AND EXTENDS FARTHER TO THE NE AS A
DISSIPATING SURFACE STATIONARY FRONT. ISOLATED SHOWERS ARE
WITHIN 60 NM EITHER SIDE OF THE STATIONARY FRONT. TO THE W OF
THIS STATIONARY FRONT...A MODIFIED CONTINENTAL POLAR AIRMASS IS
IN PLACE...WITH TEMPERATURES BELOW SEASONAL AVERAGES ACROSS
FLORIDA. THIS RELATIVELY COOLER AND DRIER AIRMASS IS BEING
REINFORCED BY A SURFACE COLD FRONT THAT EXTENDS FROM S OF
FLORIDA NEAR 24N82W TO 27N70W TO 32N65W TO NE OF THE DISCUSSION
AREA...WITH SCATTERED STRATOCUMULUS CLOUDS BETWEEN THIS FRONT
AND THE COAST OF THE SE CONUS. ANOTHER SURFACE COLD FRONT
EXTENDS FROM 31N69W TO 32N68W TO NE OF THE DISCUSSION AREA.
FARTHER TO THE E...A 1016 MB SURFACE HIGH IS CENTERED NEAR
27N54W...WHICH IS BEING SUPPORTED BY AN UPPER LEVEL RIDGE WITH
AN AXIS EXTENDING FROM 18N63W TO 23N58W TO 32N51W TO N OF THE
DISCUSSION AREA. FARTHER TO THE E...AN UPPER LOW IS CENTERED
NEAR 32N39W THAT IS ACCOMPANIED BY AN UPPER TROUGH N OF 22N
BETWEEN 24W-40W. THIS UPPER LOW AND UPPER TROUGH ARE ACCOMPANIED
A 1010 MB SURFACE LOW NEAR 30N42W...ANOTHER 1010 MB SURFACE LOW
CENTERED NEAR 29N47W...AND A SURFACE TROUGH EXTENDING FROM
22N35W TO 26N33W TO 31N34W. LOW LEVEL CONVERGENCE NEAR THESE TWO
SURFACE LOWS AND THE SURFACE TROUGH IS SUPPORTING SCATTERED
SHOWERS N OF 21N BETWEEN 24W-32W...WITH ISOLATED SHOWERS N OF
28N BETWEEN 33W-48W. OVER THE TROPICAL ATLC...AN UPPER RIDGE IS
S OF 6N BETWEEN 21W-39W. UPPER LEVEL DIVERGENCE IN THE VICINITY
OF THIS UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH
THE ITCZ...AS WELL AS THE CONVECTION ASSOCIATED WITH THE
TROPICAL WAVE ALONG 43W.

$$
COHEN

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