000
AXNT20 KNHC 272353
TWDAT 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL 
705 PM EST SAT DEC 27 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2345 UTC.

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

THE MONSOON TROUGH CROSSES THE AFRICAN COAST NEAR 07N12W AND 
CONTINUES TO 07N22W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 
06N38W TO THE COAST OF FRENCH GUIANA NEAR 04N51W. A DIFFLUENT 
ENVIRONMENT AT THE MIDDLE-LEVELS ENHANCES SCATTERED MODERATE  
CONVECTION FROM 03N-10N BETWEEN 27W AND 48W. 

...DISCUSSION...

GULF OF MEXICO... 

A SURFACE RIDGE OVER THE WESTERN ATLC ANCHORED BY A 1026 MB HIGH 
NEAR 34N72W CONTINUES TO PROVIDE E-SE FLOW OF 10-15 KT...WHICH 
IS ADVECTING MOISTURE ACROSS THE NORTHERN BASIN. A STATIONARY 
FRONT EXTENDS FROM THE SW N ATLC ACROSS NORTHERN FLORIDA TO 
SOUTHERN ALABAMA WHERE IT TRANSITIONS TO A WARM FRONT ACROSS 
SOUTHERN MISSISSIPPI. RADAR IMAGERY AND LIGHTING DATA INDICATE 
SCATTERED SHOWERS AND TSTMS ARE N OF 28N BETWEEN 87W-90W. 
FARTHER WEST...A COLD FRONT STARTS TO EMERGE FROM THE COAST OF 
TEXAS EXTENDING FROM A 1013 MB LOW NEAR 31N94W. LOW-LEVEL 
MOISTURE CONVERGENCE ENHANCES ISOLATED SHOWERS OVER THE NW GULF N 
OF 25N W OF 91W. MIDDLE- TO UPPER-LEVEL RIDGING ALONG WITH DEEP 
LAYER DRY AIR SUPPORT FAIR WEATHER ELSEWHERE. THE COLD FRONT 
WILL CONTINUE TO DRIFT EASTWARD AND START MOVING ACROSS FLORIDA 
TUE MORNING. NO MAJOR CONVECTION IS ANTICIPATED.
 
CARIBBEAN SEA...   

A VERY STABLE ENVIRONMENT ALOFT CONSISTING OF RIDGING AND DRY 
AIR SUBSIDENCE CONTINUES TO SUSTAIN CLEAR SKIES AND FAIR WEATHER 
ACROSS THE BASIN. IN TERMS OF WIND...A SURFACE RIDGE ANCHORED 
OVER THE W ATLC EXTENDS INTO THE NORTHERN CARIBBEAN AND TIGHTENS 
THE PRESSURE GRADIENT OVER THE CENTRAL BASIN TO SUPPORT TRADES 
OF 20-25 KT BETWEEN 65W-82W. TRADES OF 15 KT DOMINATE ELSEWHERE. 
HIGH PRESSURE WILL CONTINUE TO DOMINATE OVER THE NORTHERN 
CARIBBEAN THROUGH TUE MORNING...THUS SUPPORTING THE CONTINUATION 
OF 20 KT WINDS FORECAST TO EXTEND TO THE EASTERN BASIN AS THE 
HIGH PRESSURE CENTER DRIFT E-SE OVER THE ATLC WATERS.
 
HISPANIOLA...                   

CURRENTLY...MIDDLE- TO UPPER-LEVEL RIDGING AND DRY AIR 
SUBSIDENCE FROM ALOFT SUPPORT FAIR WEATHER ACROSS THE ISLAND. 
HOWEVER...A COLD FRONT OVER THE SW N ATLC WATERS IS STARTING TO 
PUSH A SHALLOW MOIST AIRMASS ACROSS THE NORTHERN ISLAND WHICH 
MAY ENHANCE ISOLATED SHOWERS LATER TONIGHT. AS THE COLD FRONT 
CONTINUES TO SINK IN THE ATLC WATERS...MOISTURE WILL 
INCREASE...THUS INCREASING THE CHANCES FOR SCATTERED SHOWERS 
STARTING SUNDAY MORNING. 

ATLANTIC OCEAN...   

A BROAD AND ELONGATED TROUGH ALOFT OVER THE CENTRAL ATLC 
CONTINUES TO SUPPORT A COLD FRONT EXTENDING FROM A 1005 MB LOW 
NEAR 30N45W AND CONTINUING SW ALONG 22N51W 21N63W TO 27N77W 
WHERE IT TRANSITIONS TO A STATIONARY FRONT ACROSS NORTHERN 
FLORIDA. SCATTERED MODERATE CONVECTION AND TSTMS ARE AHEAD OF 
THE FRONT N OF 25N BETWEEN 30W-43W. SURFACE RIDGING DOMINATES 
ELSEWHERE W AND E OF THE FRONT. THE SURFACE HIGH CENTER OVER 
MID-ATLC WATERS WILL DRIFT E-SE OVER THE NEXT TWO DAYS ALLOWING 
FOR A NEW COLD FRONT TO ENTER THE SW N ATLC ON TUE MORNING. 
 
FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
NR