517  
AXNT20 KNHC 232343  
TWDAT  
 
TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
743 PM EDT MON OCT 23 2017  
 
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  
2315 UTC.  
   
..SPECIAL FEATURES
 
 
A COLD FRONT IS CURRENTLY ANALYZED ACROSS THE GULF WATERS FROM THE  
FLORIDA BIG BEND NEAR 30N84W SW TO 23N90W WSW TO THE MEXICO COAST  
NEAR TAMPICO. A SURFACE TROUGH BOUNDARY EXTENDS SOUTHWARD FROM THE  
FRONT NEAR 21N96W TO THE MEXICO COAST NEAR 18N94W. NEAR GALE TO  
GALE FORCE NW WINDS ARE OCCURRING S OF 21N W OF 95W TO THE WEST  
OF THE SURFACE TROUGH AXIS. THE GALE FORCE WINDS ARE EXPECTED TO  
BE SHORT LIVED AS THE PRESSURE GRADIENT WEAKENS DURING THE  
OVERNIGHT HOURS. THE WIND FIELD WILL ONCE AGAIN INCREASE INTO NEAR  
GALE TO GALE FORCE CONDITIONS TUESDAY AFTERNOON AS THE COLD FRONT  
PUSHES THROUGH THE SW GULF WATERS. PLEASE SEE THE LATEST NWS HIGH  
SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR  
MORE DETAILS.  
   
..TROPICAL WAVES
 
 
A TROPICAL WAVE EXTENDS FROM 06N57W TO 17N57W MOVING W AT 10-15  
KT. THE WAVE COINCIDES WITH BROAD 700 MB TROUGHING BETWEEN 50W-  
60W AND A MAXIMUM IN 850 MB RELATIVE VORTICITY ALONG THE WAVE AXIS  
NEAR 10N. SCATTERED MODERATE CONVECTION IS FROM 07N-18N BETWEEN  
52W-62W AND CONTINUES TO BE ENHANCED BY A MIDDLE TO UPPER LEVEL  
TROUGH WITH AXIS EXTENDING FROM 21N63W SOUTHWARD TO A BROAD BASE  
OVER NORTHEASTERN SOUTH AMERICA.  
 
A TROPICAL WAVE EXTENDS FROM 10N91W TO 19N93W MOVING W AT 10-15  
KT. THE WAVE COINCIDES WITH 700 MB TROUGHING BETWEEN 87W-94W AND  
A MAXIMUM IN 850 MB RELATIVE VORTICITY ALONG THE WAVE AXIS NEAR  
17N. WIDELY SCATTERED MODERATE CONVECTION IS FROM 13N-20N BETWEEN  
88W-96W.  
   
..ITCZ/MONSOON TROUGH
 
 
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO  
10N21W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM  
10N21W TO 07N28W TO 06N45W. SCATTERED MODERATE CONVECTION IS FROM  
05N-11N BETWEEN 22W-48W.  
   
..DISCUSSION
 
 
GULF OF MEXICO...  
A VIGOROUS MIDDLE TO UPPER LEVEL TROUGH IS PROGRESSING  
NORTHEASTWARD OVER THE TENNESSEE AND OHIO RIVER VALLEYS THIS  
EVENING SUPPORTING A COLD FRONT EXTENDING FROM THE FLORIDA BIG  
BEND REGION SW TO 23N90W TO THE MEXICO COAST NEAR TAMPICO.  
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 150 NM  
EAST OF THE FRONT AND ACROSS INTERIOR PORTIONS OF NORTHERN AND  
CENTRAL FLORIDA. IN ADDITION...A SURFACE TROUGH EXTENDS FROM THE  
FRONT NEAR 21N96W TO 18N94W INDUCING THE NEAR GALE TO GALE FORCE  
NW WINDS MENTIONED ABOVE IN THE SPECIAL FEATURES SECTION.  
WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING  
GENERALLY S OF 22N BETWEEN 88W-97W. OTHERWISE...A SURFACE RIDGE  
ANCHORED BY A 1021 MB HIGH CENTERED ACROSS SE TEXAS NEAR 30N96W IS  
PROVIDING MODERATE TO FRESH N TO NE WINDS WEST OF THE FRONT. THIS  
RIDGE WILL CONTINUE TO GRADUALLY BUILD SOUTHEASTWARD THROUGH EARLY  
TUESDAY WITH A SECONDARY REINFORCING COLD FRONT...CURRENTLY ACROSS  
OKLAHOMA AND PORTIONS OF WESTERN TEXAS...EXPECTED TO SURGE SE  
TUESDAY AND TUESDAY NIGHT INCREASING NORTHERLY WINDS ACROSS MUCH  
OF THE BASIN INTO WEDNESDAY. STRONG HIGH PRESSURE IN WAKE OF THE  
FRONT WILL BUILD IN ACROSS NEW MEXICO AND TEXAS...AND INTO THE  
WESTERN GULF WEDNESDAY NIGHT INTO THURSDAY.  
 
CARIBBEAN SEA...  
AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE  
WESTERN CARIBBEAN NEAR 15N82W AND CONTINUES TO PROVIDE AN OVERALL  
DIVERGENT ENVIRONMENT ALOFT PROMOTING SCATTERED TO NUMEROUS  
SHOWERS AND SCATTERED STRONG TSTMS FROM 11N-20N BETWEEN 78W-  
88W...INCLUDING INLAND PORTIONS OF CENTRAL AMERICA. AT THE  
SURFACE...THIS ACTIVITY FOCUSED ON MAXIMIZED MOISTURE CONVERGENCE  
NEAR A SURFACE TROUGH ANALYZED FROM 12N82W TO 18N86W. FARTHER  
SOUTH...THE ADDITION OF THE MONSOON TROUGH AXIS ALONG 11N BETWEEN  
NORTHERN COLOMBIA AND COSTA RICA IS ALSO PROVIDING FOCUS FOR  
SCATTERED SHOWERS AND TSTMS S OF 11N BETWEEN 71W-86W. FINALLY...A  
TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES CURRENTLY NOTED  
ALONG 58W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 07N-18N  
BETWEEN 52W-62W AND THIS AREA IS EXPECTED TO CONTINUE MOVING  
WESTWARD. ENHANCING PORTIONS OF THIS CONVECTION IS AN UPPER LEVEL  
LOW CENTERED TO THE N-NW NEAR 22N63W. OTHERWISE...MODERATE TO  
FRESH TRADES PREVAIL ACROSS THE BASIN THIS EVENING.  
   
..HISPANIOLA
 
 
DRY AIR ALOFT WITHIN NORTHERLY FLOW WILL SUPPORT FAIR WEATHER  
ACROSS THE ISLAND THROUGH TUESDAY. MODERATE TO FRESH TRADES ARE  
EXPECTED THROUGH WEDNESDAY.  
 
ATLANTIC OCEAN...  
MUCH OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A SURFACE  
RIDGE ANCHORED BY 1032 MB HIGH CENTERED NEAR 41N61W. WITHIN THE  
WESTERN PERIPHERY OF THIS RIDGING...UPPER LEVEL DIVERGENCE IS  
MAXIMIZED WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING N OF  
27N W OF 75W AS A COLD FRONT APPROACHES THE EASTERN SEABOARD THIS  
EVENING INTO EARLY TUESDAY. OTHERWISE...WITHIN THE SOUTHERN  
PERIPHERY OF THE RIDGE...MODERATE TO FRESH E-SE WINDS ARE  
OCCURRING GENERALLY W OF 62W. FARTHER EAST...AN UPPER LEVEL LOW IS  
CENTERED NEAR 22N63W. THE UPPER LEVEL LOW SUPPORTS A SURFACE  
TROUGH EXTENDING FROM 20N58W TO 26N58W WITH SCATTERED SHOWERS AND  
TSTMS OCCURRING FROM 22N-29N BETWEEN 52W-63W. THIS AREA LIES SW OF  
A COLD FRONT EXTENDING INTO THE DISCUSSION AREA NEAR 32N38W  
EXTENDING SW TO 28N48W THEN STATIONARY TO N OF THE SURFACE  
TROUGHING NEAR 28N57W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS  
ARE POSSIBLE WITHIN 120 NM EITHER SIDE OF THE FRONTAL BOUNDARY.  
FINALLY...ANOTHER MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED  
ON WATER VAPOR IMAGERY IN THE VICINITY OF 28N28W. THIS FEATURE  
SUPPORTS ANOTHER WEAK SURFACE TROUGH EXTENDING FROM 23N28W TO  
29N21W AND PROVIDES FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS  
OCCURRING FROM 19N-31N BETWEEN 23W-30W.  
 
FOR ADDITIONAL INFORMATION PLEASE VISIT  
HTTP://WWW.HURRICANES.GOV/MARINE  
 

 
HUFFMAN  
 
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