[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 040001
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU JUL 03 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
2315 UTC.

...SPECIAL FEATURES...
HURRICANE ARTHUR IS CENTERED NEAR 34.0N 77.2W AT 04/0000 UTC OR
ABOUT 40 NM E OF CAPE FEAR NORTH CAROLINA AND ABOUT 110 NM SW OF
CAPE HATTERAS NORTH CAROLINA MOVING N-NE AT 13 KT. ESTIMATED
MINIMUM CENTRAL PRESSURE IS 977 MB. MAXIMUM SUSTAINED WIND SPEED
IS 80 KT WITH GUSTS OF 100 KT. NUMEROUS MODERATE CONVECTION IS
FROM 32N-38N BETWEEN 75W-80W. SEE LATEST INTERMEDIATE PUBLIC
ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT1/WTNT31 KNHC AND THE
FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT1/WTNT21
KNHC FOR MORE DETAILS.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 11N19W TO 19N17W MOVING W AT 10-15
KT. EXAMINING UPPER AIR TIME SECTION ANALYSES...THE WAVE HAS
PASSED DAKAR SENEGAL AND COINCIDES WITH A GLOBAL MODEL INDICATED
700 MB TROUGH AXIS BETWEEN 14W-22W. A STRONG SAHARAN AIR LAYER
SIGNAL IS NOTED ON METEOSAT-9 IMAGERY TO THE WEST AND NORTH OF
THE WAVE...WHILE GENERAL LOW-LEVEL CONVERGENCE TO THE EAST IS
GENERATING SCATTERED MODERATE CONVECTION ACROSS INLAND PORTIONS
OF WEST AFRICA FROM 08N-18N BETWEEN 07W-14W.

TROPICAL WAVE EXTENDS FROM 11N46W TO 21N46W MOVING W AT 15-20
KT. THE WAVE IS ASSOCIATED WITH WEAK 700 MB TROUGHING AND A
BROAD AREA OF 850 MB RELATIVE VORTICITY FROM 10N-18N BETWEEN 40W-
50W. THERE IS NO SIGNIFICANT DEEP CONVECTION OCCURRING AT THIS
TIME WITH THE WAVE DUE TO BEING EMBEDDED WITHIN A STRONG SAHARAN
AIR LAYER.

TROPICAL WAVE EXTENDS FROM 13N70W TO 22N63W MOVING W AT 15-20
KT. THE WAVE IS CURRENTLY MOVING BENEATH A BROAD ELONGATED
UPPER LEVEL LOW CENTERED OVER THE MONA PASSAGE NEAR 18N68W. DUE
TO THE RELATIVELY UNFAVORABLE ENVIRONMENT OF UPPER LEVEL WIND
SHEAR IMPACTING THE WAVE...NO SIGNIFICANT CONVECTION IS
ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N88W TO 21N86W MOVING W-NW AT 15
KT. THE WAVE IS BEGINNING TO REACH THE WESTERN PERIPHERY OF A
MID-LEVEL RIDGE CENTERED OVER THE FLORIDA STRAITS NEAR 24N78W
AND IS EXPECTED TO CONTINUE PROVIDING HIGHER PROBABILITY
PRECIPITATION CHANCES FOR CENTRAL AMERICA AND THE YUCATAN
PENINSULA DURING THE NEXT 24 TO 36 HOURS. WIDELY SCATTERED
MODERATE CONVECTION IS FROM 11N-22N BETWEEN 84W-92W.

TROPICAL WAVE EXTENDS FROM 14N96W TO 22N95W MOVING W AT 10-15
KT. THE WAVE CONTINUES ON A WEAKENING TREND AS THE NORTHERN
PERIPHERY OF THE WAVE COMES UNDER THE INFLUENCE OF THE BASE OF
AN UPPER LEVEL LOW CENTERED OVER THE NW GULF OF MEXICO NEAR
26N96W. ISOLATED MODERATE CONVECTION IS FROM 20N-24N BETWEEN 92W-
97W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO
07N26W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM
07N26W TO 04N31W TO 07N37W TO 05N43W TO 05N52W. ISOLATED
MODERATE CONVECTION IS FROM 04N-06N BETWEEN 19W-29W.

...DISCUSSION...

GULF OF MEXICO...
A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH IS OVER THE GREAT LAKES
REGION THIS EVENING THAT SUPPORTS AN AREA OF LOWER PRESSURE
ACROSS THE EASTERN SEABOARD FROM NEW ENGLAND S-SW TO NORTHERN
FLORIDA. A 1013 MB LOW IS CENTERED IN EXTREME WESTERN SOUTH
CAROLINA NEAR 35N83W WITH A COLD FRONT EXTENDING ACROSS CENTRAL
GEORGIA...SE ALABAMA TO THE MISSISSIPPI RIVER DELTA REGION NEAR
29N90W TO THE TEXAS COAST NEAR 30N94W. WHILE THE WESTERN PORTION
OF THE FRONT CONTINUES TO WEAKEN AND DISSIPATE...AN UPPER LEVEL
LOW IS CENTERED OVER THE NW GULF WATERS NEAR 26N96W THAT
SUPPORTS A PRE-FRONTAL SURFACE TROUGH EXTENDING FROM 29N87W SW
TO 25N93W. SCATTERED SHOWERS AND TSTMS ARE OCCURRING PRIMARILY
BETWEEN THE COLD FRONT AND SURFACE TROUGH BOUNDARIES FROM 25N-
29N BETWEEN 88W-93W. ACROSS THE SW GULF...A TROPICAL WAVE
EXTENDS SOUTH OF 22N ALONG 95W AND IS GENERATING WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-25N BETWEEN 92W-
97W. LOOKING AHEAD...THE FRONTAL TROUGHING IS FORECAST TO DRIFT
GRADUALLY EAST AND BECOME QUASI-STATIONARY ACROSS THE EASTERN
GULF THROUGH SATURDAY AS SURFACE RIDGING SLOWLY BUILDS IN ACROSS
THE WESTERN GULF AND EVENTUALLY THE EASTERN GULF BY SUNDAY.

CARIBBEAN SEA...
TWO TROPICAL WAVES ARE IMPACTING THE CARIBBEAN SEA THIS
EVENING...ONE ACROSS THE NW CARIBBEAN AND HONDURAS GENERATING
SCATTERED SHOWERS AND TSTMS FOR MUCH OF CENTRAL AMERICA AND THE
YUCATAN PENINSULA...AND THE OTHER EXTENDING FROM PUERTO RICO S-
SW TO NE OF ARUBA NEAR 13N70W. THE CONVECTION ASSOCIATED WITH
THE WESTERNMOST WAVE IS LIKELY ENHANCED DUE TO THE PRESENCE OF
AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED NEAR 13N86W.
OTHERWISE...THE EASTERNMOST WAVE IS UNDER THE INFLUENCE OF AN
UPPER LEVEL LOW CENTERED OVER THE MONA PASSAGE NEAR 18N68W.
AMPLE UPPER LEVEL WIND SHEAR IS INHIBITING ANY SIGNIFICANT
CONVECTION FROM DEVELOPING...HOWEVER A FEW ISOLATED SHOWERS ARE
POSSIBLE N OF 16N BETWEEN 65W-73W. FINALLY...GENTLE TO FRESH
TRADE WINDS ARE EXPECTED TO PERSIST THROUGH THE OVERNIGHT HOURS
INTO FRIDAY WITH SLIGHTLY STRONGER WINDS 25 TO 30 KT NOTED IN
CLOSE PROXIMITY TO THE COLOMBIA COAST AS INDICATED BY EARLIER
ASCAT PASSES AROUND 03/1416 UTC AND 03/1504 UTC.

...HISPANIOLA...
CURRENTLY ONLY A FEW ISOLATED SHOWERS ARE NOTED ON SATELLITE
IMAGERY AND CONTINUE TO DIMINISH WITH THE LOSS OF PEAK DAYTIME
HEATING AND INSTABILITY. A TROPICAL WAVE LIES TO THE EAST OF THE
ISLAND ACROSS PUERTO RICO AND IS EXPECTED TO MOVE ACROSS THE
ISLAND OVERNIGHT INTO FRIDAY. PRECIPITATION CHANCES ARE EXPECTED
TO REMAIN FAIRLY LIMITED WITH THE PASSAGE OF THE WAVE DUE TO A
MODEST AMOUNT OF SAHARAN AIR AND DUST SURROUNDING THE WAVE AND
THE INCREASED UPPER LEVEL WIND SHEAR ENVIRONMENT DUE AN UPPER
LEVEL LOW CENTERED NEAR 18N68W.

ATLANTIC OCEAN...
ASIDE FROM HURRICANE ARTHUR MENTIONED ABOVE CURRENTLY NORTH OF
THE DISCUSSION AREA...THE SW NORTH ATLC IS UNDER THE INFLUENCE
OF WEAK SURFACE RIDGING EXTENDING FROM BERMUDA NEAR 32N65W SW TO
THE CENTRAL BAHAMAS. ONLY A FEW ISOLATED SHOWERS ARE OCCURRING
ACROSS THE AREA FROM 23N-29N BETWEEN 63W-70W. FARTHER EAST...AN
UPPER LEVEL LOW IS CENTERED NEAR 38N56W AND SUPPORTS A WEAK 1023
MB LOW CENTERED NEAR 36N55W. A SURFACE TROUGH EXTENDS FROM THE
LOW TO 30N56W THEN SW TO 24N62W. ISOLATED SHOWERS ARE POSSIBLE
WITHIN 90 NM EITHER SIDE OF THE SURFACE TROUGH AXIS.
OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS
UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1033 MB
HIGH CENTERED SW OF THE AZORES NEAR 38N31W. A LARGE AREA OF
SAHARAN DUST COVERS A MAJORITY OF THE ATLC S OF 32N E OF 50W.

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

$$
HUFFMAN


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