[Tropical] Tropical Weather Discussion

[EMWIN Server]

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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