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AXNT20 KNHC 311043
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU JUL 31 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 1015 UTC.


...SPECIAL FEATURES... A 1010 MB LOW IS CENTERED NEAR 11N49W MOVING W-NW AT 15 KT. THE LOW CONTINUES TO SHOW A MARGINALLY IMPRESSIVE SATELLITE PRESENTATION. DURING THE PAST FEW HOURS HOWEVER...THE LOW-LEVEL CIRCULATION CENTER HAS BECOME PARTIALLY EXPOSED TO THE WEST OF THE STRONGEST CONVECTION. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 120 NM OF THE CENTER IN THE SE SEMICIRCLE. IN ADDITION...EARLIER EVENING ASCAT PASSES AROUND 31/0022 UTC AND 31/0110 UTC INDICATED A 20 TO 30 KT WIND FIELD SURROUNDING THE LOW WITHIN 90 NM OF CENTER. PLEASE SEE THE LATEST NHC TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC FOR MORE DETAILS.


...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N30W TO 16N31W MOVING W AT 5-10 KT. A BROAD LOW-LEVEL...850 MB-700 MB...CYCLONIC CIRCULATION IS NOTED IN THE VICINITY OF THE WAVE AND ACROSS AN AREA FOCUSED NEAR A 1012 MB SURFACE LOW CENTERED AT THE SOUTHERN EXTENT OF THE WAVE AXIS NEAR 09N30N. THE BROAD AREA OF 850 MB RELATIVE VORTICITY IS NOTED FROM 08N-11N BETWEEN 28W-33W. CONVECTION REMAINS LIMITED DUE TO THE SAHARAN AIR LAYER COVERING MUCH OF THE TROPICAL ATLC...HOWEVER WIDELY SCATTERED MODERATE CONVECTION IS FROM 08N-13N BETWEEN 30W-34W.

TROPICAL WAVE EXTENDS FROM 10N56W TO 20N58W MOVING W AT 15-20 KT. THE WAVE REMAINS TO THE W-NW OF THE SPECIAL FEATURES 1010 MB SURFACE LOW CENTERED NEAR 11N49W. A PORTION OF ENERGY ASSOCIATED WITH THE WAVE HAS FRACTURED TO THE NORTH...LARGELY STRETCHING OF THE 700 MB TROUGHING...AND IS ANALYZED AS A SURFACE TROUGH FROM 21N58W TO 25N56W. SATELLITE IMAGERY AND GLOBAL MODEL DATA INDICATE THE REMAINDER OF THE WAVE ENERGY IS EMBEDDED WITHIN A 700 MB TROUGH THAT COINCIDES WITH THE WAVE AXIS. NO SIGNIFICANT DEEP CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.


...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 19N17W TO 13N20W TO A 1012 MB LOW PRES NEAR 09N31W TO 05N40W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 12W- 20W...AND FROM 04N-08N BETWEEN 31W-40W.


...DISCUSSION...

GULF OF MEXICO... BROAD LONGWAVE UPPER LEVEL TROUGHING IS OVER THE EASTERN CONUS THAT SUPPORTS A 1014 MB LOW CENTERED NEAR JACKSONVILLE FLORIDA WITH A STATIONARY FRONT ANALYZED SOUTHWARD ACROSS THE SPINE OF THE FLORIDA PENINSULA AND INTO THE GULF WATERS NEAR FORT MYERS. THE FRONT CONTINUES SW TO 24N86W THEN NW TO 25N90W WHERE IT BEGINS DISSIPATING TO THE TEXAS COAST NEAR 29N95W. ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 45 NM EITHER SIDE OF THE FRONT AND N OF 24N BETWEEN 81W-83W. OTHERWISE...A SURFACE RIDGE IS ANCHORED ON EITHER SIDE OF THE FRONTAL BOUNDARY WITH A RIDGE AXIS EXTENDING ALONG 22N ACROSS CUBA TO THE EAST MEXICO COAST. TO THE NORTH OF THE FRONT...THE OTHER SURFACE RIDGE IS ANCHORED BY A 1017 MB HIGH CENTERED OVER SOUTHERN MISSISSIPPI NEAR 31N90W. LOOKING AHEAD...THE FRONTAL BOUNDARY IS FORECAST TO BECOME DIFFUSE THROUGH FRIDAY. MEANWHILE...WEAK RIDGING IS EXPECTED TO REMAIN ACROSS THE WESTERN AND CENTRAL GULF THROUGH FRIDAY.

CARIBBEAN SEA... RELATIVELY DRY AND STABLE CONDITIONS ALOFT ARE NOTED OVER MUCH OF THE CARIBBEAN THIS MORNING FOCUSED ON AN ELONGATED UPPER LEVEL LOW CENTERED NEAR 17N81W AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 11N66W. GIVEN MARGINAL LIFTING DYNAMICS IN ASSOCIATION WITH THE UPPER LEVEL LOW...ISOLATED SHOWERS AND TSTMS ARE OCCURRING WITHIN 90 NM OF THE SOUTHERN COAST OF CUBA. OTHERWISE...CONDITIONS ACROSS THE NW CARIBBEAN REMAIN FAIR WITH MOSTLY CLEAR SKIES THIS MORNING. FARTHER EAST...MOSTLY CLEAR SKIES PREVAIL WITH THE UPPER LEVEL RIDGING PROVIDING AN OVERALL SUBSIDENT ENVIRONMENT...HOWEVER LOW-LEVEL MOISTURE INCREASES E OF 66W WITH THE APPROACH OF A TROPICAL WAVE CURRENTLY ALONG 58W. OTHERWISE...THE ONLY OTHER CONVECTION OCCURRING IS SCATTERED SHOWERS AND TSTMS ALONG THE COASTS OF PANAMA AND COSTA RICA S OF 11N BETWEEN 77W-83W DUE TO THE CLOSE PROXIMITY OF THE MONSOON TROUGH ALONG 08N/09N. FINALLY... MODERATE TO FRESH TRADES PERSIST WITH THE STRONGEST AREA OF WINDS EXPECTED S OF 14N BETWEEN 68W-77W.


...HISPANIOLA... CURRENTLY...THE ISLAND REMAINS NEAR THE BASE OF AN UPPER LEVEL LOW CENTERED IN THE SW NORTH ATLC NEAR 25N65W. WITH THE UPPER LEVEL TROUGHING EXPECTED TO MOVE LITTLE DURING THE NEXT 24 HOURS...AN OVERALL DIFFLUENT ENVIRONMENT WILL REMAIN IN PLACE ACROSS HISPANIOLA WITH SCATTERED SHOWERS AND TSTMS FORECAST THURSDAY AFTERNOON INTO THE EVENING WITH PEAK DAYTIME HEATING AND INSTABILITY.

ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS OVER THE EASTERN CONUS REMAINING LARGELY N OF 31N THAT SUPPORTS A 1014 MB LOW CENTERED NEAR JACKSONVILLE FLORIDA WITH A STATIONARY FRONT EXTENDING EAST FROM THE LOW CENTER TO 30N77W THEN NE TO BEYOND 32N74W. ISOLATED SHOWERS ARE OCCURRING NW OF A LINE FROM 24N79W TO 32N72W TO THE FRONTAL BOUNDARY. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 25N65W WITH MID-LEVEL ENERGY FOCUSED NEARLY IN THE SAME LOCATION THAT SUPPORTS AN AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 18N-28N BETWEEN 61W-70W. OTHERWISE...THE REMAINDER OF THE CENTRAL ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 38N57W. ON THE EASTERN PERIPHERY OF THIS RIDGE HOWEVER...A MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY WITH SHORTWAVE ENERGY LOCATED IN THE VICINITY OF 29N43W. AS THE SHORTWAVE MOVES E-SE...IT CONTINUES TO PRODUCE A BROAD AREA OF SCATTERED SHOWERS AND TSTMS FROM 28N-32N BETWEEN 44W-51W. THIS ACTIVITY REMAINS FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM A 1016 MB LOW NEAR 34N32W SW TO ANOTHER 1016 MB LOW NEAR 30N42W WESTWARD TO 29N53W. OTHERWISE...THIS BROADER AREA OF LOWER PRESSURE IS ANALYZED E OF 50W WITH SKIES REMAINING MOSTLY FAIR.

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

$$ HUFFMAN

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