[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 310553
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...SPECIAL FEATURES...
A 1010 MB LOW IS CENTERED NEAR 11N48W MOVING W-NW AT 15 KT. THE
LOW LIES WITHIN THE MONSOON TROUGH AXIS AND CONTINUES TO SHOW A
MARGINALLY IMPRESSIVE SATELLITE PRESENTATION. DURING THE PAST
FEW HOURS HOWEVER...A ONCE EXPOSED LOW-LEVEL CIRCULATION CENTER
HAS SEEN A BURST OF SCATTERED MODERATE CONVECTION FORM WITHIN 45
NM OF THE CIRCULATION CENTER. IN ADDITION...EARLIER EVENING
ASCAT PASSES AROUND 31/0022 UTC AND 31/0110 UTC INDICATE 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 10N30W TO 17N30W MOVING W AT 15 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
1011 MB SURFACE LOW CENTERED AT THE SOUTHERN EXTENT OF THE WAVE
AXIS NEAR 10N30N. 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 ISOLATED MODERATE CONVECTION IS FROM 09N-12N
BETWEEN 29W-33W.

TROPICAL WAVE EXTENDS FROM 11N54W TO 18N56W MOVING W AT 15-20
KT. THE WAVE REMAINS TO THE W-NW OF THE SPECIAL FEATURES 1010 MB
SURFACE LOW CENTERED ALONG THE MONSOON TROUGH NEAR 11N48W.
SATELLITE IMAGERY AND GLOBAL MODEL DATA INDICATE THE WAVE IS
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 12N17W TO
A 1011 MB LOW PRES NEAR 10N30W TO 05N37W TO A 1010 MB LOW PRES
NEAR 11N48W TO 06N53W. ISOLATED MODERATE CONVECTION IS FROM 06N-
13N BETWEEN 09W-18W. SCATTERED MODERATE CONVECTION IS FROM 05N-
09N BETWEEN 31W-37W...AND FROM 08N-10N BETWEEN 49W-52W.

...DISCUSSION...

GULF OF MEXICO...
BROAD LONGWAVE UPPER LEVEL TROUGHING IS OVER THE EASTERN CONUS
THAT AS OF 31/0300 UTC SUPPORTS A 1015 MB LOW CENTERED NEAR
JACKSONVILLE FLORIDA WITH A COLD FRONT ANALYZED SOUTHWARD ACROSS
THE SPINE OF THE FLORIDA PENINSULA AND INTO THE GULF WATERS NEAR
FORT MYERS. THE FRONT CONTINUES SW TO 25N86W THEN NW TO 26N91W
WHERE IT BECOMES STATIONARY TO THE TEXAS COAST NEAR 29N95W.
WIDELY SCATTERED SHOWERS AND ISOLATED SHOWERS ARE OCCURRING
ACROSS THE SOUTHERN FLORIDA PENINSULA S OF 27N AND WITHIN 45 NM
EITHER SIDE OF THE COLD FRONT OVER THE EASTERN GULF WATERS.
OTHERWISE...A SURFACE RIDGE IS ANCHORED ON EITHER SIDE OF THE
FRONTAL BOUNDARY WITH A RIDGE AXIS EXTENDING ALONG 21N ACROSS
CUBA...THE YUCATAN PENINSULA...TO THE EAST MEXICO COAST. TO THE
NORTH OF THE FRONT...THE OTHER SURFACE RIDGE IS ANCHORED BY A
1019 MB HIGH CENTERED OVER WESTERN KENTUCKY NEAR 36N88W. LOOKING
AHEAD...THE FRONTAL BOUNDARY IS FORECAST TO DRIFT SOUTH ACROSS
THE EASTERN GULF WATERS THROUGH EARLY FRIDAY AND BECOME DIFFUSE
THROUGH THAT TIME. 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 EVENING FOCUSED ON AN UPPER LEVEL LOW
CENTERED NEAR 17N82W 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...AND FROM 16N-19N BETWEEN 83W-86W. OTHERWISE...CONDITIONS
ACROSS THE NW CARIBBEAN REMAIN FAIR WITH MOSTLY CLEAR SKIES THIS
EVENING. FARTHER EAST...MOSTLY CLEAR SKIES PREVAIL WITH THE
UPPER LEVEL RIDGING PROVIDING AN OVERALL SUBSIDENT
ENVIRONMENT...HOWEVER LOW-LEVEL MOISTURE INCREASES E OF 65W WITH
THE APPROACH OF A TROPICAL WAVE CURRENTLY ALONG 55W.
OTHERWISE...THE ONLY OTHER CONVECTION OCCURRING IS SCATTERED
SHOWERS AND TSTMS ALONG THE COASTS OF PANAMA AND COSTA RICA S OF
11N BETWEEN 80W-85W 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 25N66W. A FEW LINGERING
ISOLATED SHOWERS AND TSTMS ARE OCCURRING W OF 71W...AND THIS
ACTIVITY IS EXPECTED TO DIMINISH THROUGH THE OVERNIGHT HOURS.
WITH THE UPPER LEVEL LOW 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 32N THAT AS OF 31/0300 UTC SUPPORTS A 1015 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 WITHIN 60 NM S OF THE
STATIONARY FRONT AND N OF 24N W OF 78W TO THE FLORIDA PENINSULA
COAST. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 25N66W
WITH MID-LEVEL ENERGY FOCUSED NEARLY IN THE SAME LOCATION THAT
SUPPORTS AN AREA OF WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS
FROM 18N-27N BETWEEN 61W-70W. OTHERWISE...THE REMAINDER OF THE
CENTRAL ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED
BY A 1029 MB HIGH CENTERED NEAR 36N57W. 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 28N46W. AS THE SHORTWAVE MOVES E-SE...IT CONTINUES
TO PRODUCE SCATTERED SHOWERS AND TSTMS FROM 28N-33N BETWEEN 43W-
51W. OTHERWISE...A BROAD AREA OF LOWER PRESSURE IS ANALYZED E OF
40W WITH SKIES REMAINING MOSTLY FAIR FOR THE OVERNIGHT PERIOD.

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

$$
HUFFMAN

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