[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 301024
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1030 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN WITH AXIS
EXTENDING FROM 18N71W TO 11N72W...MOVING W AT 15 KT. THE WAVE IS
BEING SUPPORTED BY AN INVERTED TROUGH AT 700 MB 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 11N15W AND CONTINUES TO 8N25W. THE ITCZ BEGINS NEAR
8N25W AND CONTINUES ALONG 9N38W TO 9N49W. SCATTERED SHOWERS ARE
FROM 5N-11N E OF 40W. A SURFACE TROUGH IS WEST OF THE ITCZ ALONG
13N48W TO 6N51W. SCATTERED SHOWERS ARE WITHIN 160 NM EITHER SIDE
OF THE TROUGH AXIS.

...DISCUSSION...

GULF OF MEXICO...

A COLD FRONT BEING SUPPORTED BY A BROAD MIDDLE- TO UPPER-LEVEL
TROUGH OVER THE EASTERN CONUS EXTENDS INTO THE NORTHERN GULF
FROM FLORIDA NEAR 30N82W TO 28N90W TO CORPUS CHRISTI TEXAS.
ISOLATED SHOWERS ARE WITHIN 60 NM EITHER SIDE 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
28N85W TO 24N85W WITH SHOWERS AND TSTMS BEING ALONG THE TROUGH
AXIS. ANOTHER WEAKNESS IN THE RIDGE IS BEING ANALYZED AS A
SURFACE TROUGH OVER THE BAY OF CAMPECHE ALONG 23N93W TO 18N93W.
SHALLOW MOISTURE ADVECTED TO THE SW GULF FROM THE REMNANTS OF
TROPICAL CYCLONE HANNA SUPPORTS SCATTERED SHOWERS WITHIN 160 NM
EITHER SIDE OF THE TROUGH AXIS. THE COLD FRONT WILL MOVE ACROSS
THE NORTHERN AND CENTRAL FLORIDA PENINSULA THROUGH TONIGHT 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...SCATTERED MODERATE CONVECTION IS S OF
12N BEING ENHANCED BY THE MONSOON TROUGH THAT CROSSES CENTRAL
PANAMA TO NW COLOMBIA. A TROPICAL WAVE IS MOVING OVER THE
CENTRAL CARIBBEAN BEING SUPPORTED BY AN INVERTED LOW-LEVEL
TROUGH...HOWEVER STRONG DRY AIR SUBSIDENCE FROM ALOFT IN THIS
REGION OF THE BASIN ALONG WITH STRONG DEEP LAYER ENVIRONMENTAL
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 INTO A SURFACE TROUGH WITH
THE SOUTHERN END 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 IMMEDIATE 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 28N71W TO 23N73W THAT IS ENHANCING ISOLATED
SHOWERS AND TSTMS FROM 24N-29N BETWEEN 69W-73W. NE OF THE VIRGIN
ISLANDS...AN AREA OF LOW PRESSURE ANALYZED AS A 1009 MB LOW NEAR
19N64W CONTINUES TO SUPPORT A CLUSTER OF MODERATE TO ISOLATED
STRONG CONVECTION FROM 18N-20N BETWEEN 60W-63W AND SCATTERED
SHOWERS ELSEWHERE FROM 17N-24N BETWEEN 57W-63W. A MIDDLE TO
UPPER LEVEL TROUGH OVER THE CENTRAL ATLC CONTINUE TO SUPPORT A
COLD FRONT ANALYZED FROM 30N34W SW TO 25N48W WHERE IT
TRANSITIONS TO A DISSIPATING STATIONARY FRONT TO 25N54W.
SCATTERED SHOWERS ARE WEST OF THE TAIL OF THE FRONT FROM 24N-28N
BETWEEN 57W-63W.

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

$$
NR


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