[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 300602
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU OCT 30 2014

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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 17N70W TO 11N71W...MOVING W AT 15 KT. THE WAVE IS
BEING SUPPORTED BY A LOW- TO MIDDLE-LEVEL INVERTED TROUGH AND
CONTINUES EMBEDDED IN A SHALLOW MODERATE MOIST ENVIRONMENT. DRY
AIR SUBSIDENCE FROM ALOFT IN THIS REGION OF THE BASIN ALONG WITH
STRONG DEEP LAYER ENVIRONMENTAL SHEAR INHIBIT THE DEVELOPMENT OF
CONVECTION AT THE TIME.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 10N14W AND CONTINUES TO 7N23W. THE ITCZ BEGINS NEAR
7N23W AND CONTINUES ALONG 5N34W TO 5N44W. SCATTERED SHOWERS ARE
FROM 4N-10N E OF 32W. SCATTERED MODERATE CONVECTION IS FROM 8N-
17N BETWEEN 33W-39W. A SURFACE TROUGH IS WEST OF THE ITCZ ALONG
12N48W TO 4N48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS FROM 7N-11N BETWEEN 47W-53W.

...DISCUSSION...

GULF OF MEXICO...

A COLD FRONT EXTENDS ACROSS THE SE CONUS INTO THE NORTHERN GULF
FROM PENSACOLA FLORIDA TO NEW ORLEANS TO HOUSTON TEXAS...WHICH
IS BEING SUPPORTED BY A BROAD MIDDLE- TO UPPER-LEVEL TROUGH OVER
THE EASTERN CONUS. ISOLATED SHOWERS ARE WITHIN 60 NM S OF THE
FRONT. WEAK SURFACE RIDGING IS AHEAD OF THE COLD FRONT ACROSS
THE BASIN...WHICH IS PROVIDING WITH N-NE WIND FLOW IN THE RANGE
OF 5-10 KT. A SURFACE PRE-FRONTAL TROUGH IS OVER THE E GULF
ALONG 29N86W TO 24N86W WITH NO SHOWERS ASSOCIATED WITH IT DUE TO
STRONG DEEP LAYER ENVIRONMENTAL SHEAR AND DRY AIR ACROSS THE
REGION. ANOTHER WEAKNESS IN THE RIDGE IS BEING ANALYZED AS A
SURFACE TROUGH OVER THE BAY OF CAMPECHE ALONG 24N92W TO 17N95W.
SHALLOW MOISTURE ADVECTED TO THE SW GULF FROM THE REMNANTS OF
TROPICAL CYCLONE HANNA SUPPORTS SCATTERED SHOWERS WITHIN 200 NM
EITHER SIDE OF THE TROUGH AXIS. THE COLD FRONT WILL MOVE ACROSS
THE NORTHERN AND CENTRAL FLORIDA PENINSULA THROUGH THU NIGHT AND
OVER SOUTH FLORIDA THROUGH FRIDAY NIGHT. A STRONG SURFACE RIDGE
BUILDS BEHIND THE FRONT THROUGH THE REMAINDER WEEKEND.

CARIBBEAN SEA...

DEEP LAYER MOISTURE ASSOCIATED WITH FORMER TROPICAL CYCLONE
HANNA LINGERS IN THE NW CARIBBEAN AND NORTHERN CENTRAL
AMERICA...WHICH ALONG A DIVERGENT ENVIRONMENT ALOFT CONTINUE TO
FUEL SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS S OF 20N W
OF 81W. IN THE SW BASIN...ISOLATED MODERATE CONVECTION IS S OF
11N BEING ENHANCED BY THE MONSOON TROUGH THAT CROSSES PANAMA TO
NW COLOMBIA. A TROPICAL WAVE IS MOVING OVER THE CENTRAL BASIN
BEING SUPPORTED BY AN INVERTED LOW- TO MIDDLE-LEVEL
TROUGH...HOWEVER STRONG DRY AIR SUBSIDENCE FROM ALOFT IN THIS
REGION OF THE BASIN ALONG WITH STRONG WIND SHEAR HINDER THE
DEVELOPMENT OF DEEP CONVECTION. SEE TROPICAL WAVES SECTION ABOVE
FOR MORE DETAILS. AN AREA OF LOW PRESSURE CENTERED NE OF THE
VIRGIN ISLANDS IS ADVECTING MOISTURE TO PUERTO RICO AND
HISPANIOLA THAT IS ENHANCING ISOLATED SHOWERS AT THE TIME. MODEL
GUIDANCE INDICATE THE WAVE WILL CONTINUE TO MOVE TOWARDS WESTERN
CARIBBEAN WATERS THROUGH THE WEEKEND. THE AREA OF LOW PRESSURE
WILL DRIFT W-NW THROUGH FRIDAY NIGHT WHEN IT IS FORECAST TO
TRANSITION TO A SURFACE TROUGH BRUSHING NORTHERN HISPANIOLA.

HISPANIOLA...

SHALLOW MOISTURE ASSOCIATED WITH AN AREA OF LOW PRESSURE NE OF
THE VIRGIN ISLANDS IS BEING ADVECTED ACROSS THE ISLAND BY NE
WIND FLOW. THIS IS ENHANCING ISOLATED SHOWERS ACROSS THE ISLAND
AND ADJACENT WATERS. SHOWER ACTIVITY IS EXPECTED TO INCREASE
THROUGH FRIDAY NIGHT WHEN THE AREA OF LOW PRESSURE WEAKEN INTO A
TROUGH JUST N OF THE ISLAND.

ATLANTIC OCEAN...

A SHORT-WAVE UPPER-LEVEL TROUGH OVER THE SW N ATLC SUPPORT A
SURFACE TROUGH ALONG 25N70W TO 21N72W THAT IS ENHANCING ISOLATED
SHOWERS AND TSTMS FROM 25N-27N BETWEEN 68W-72W. NE OF THE VIRGIN
ISLANDS...AN AREA OF LOW PRESSURE ANALYZED AS A 1009 MB LOW NEAR
19N63W CONTINUE TO SUPPORT A CLUSTER OF MODERATE TO ISOLATED
STRONG CONVECTION FROM 18N-21N BETWEEN 59W-63W. A MIDDLE TO
UPPER LEVEL TROUGH OVER THE CENTRAL ATLC CONTINUE TO SUPPORT A
COLD FRONT ANALYZED FROM 30N37W SW TO 26N51W WHERE IT
TRANSITIONS TO A STATIONARY FRONT TO 26N63W. SCATTERED SHOWERS
ARE NEAR THE TAIL OF THE FRONT FROM 22N-28N BETWEEN 55W-64W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR


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