Tropical Weather Discussion
Issued by NWS

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000
AXNT20 KNHC 170541
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT THU JUL 17 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.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 09N19W TO 16N18W MOVING W AT 10-15
KT. A FAIRLY IMPRESSIVE AMOUNT OF CONVECTION IS ASSOCIATED WITH
THE WAVE ACROSS WEST AFRICA AT THIS TIME IN AN AREA OF MAXIMUM
LOW-LEVEL MOISTURE CONVERGENCE TO THE EAST OF THE WAVE AXIS.
SCATTERED MODERATE AND STRONG CONVECTION IS FROM 06N-17N BETWEEN
09W-17W.

TROPICAL WAVE EXTENDS FROM 05N36W TO 12N34W MOVING W AT 15 KT.
THE WAVE COINCIDES WITH WEAK 700 MB TROUGHING BETWEEN 33W-
39W...AND A BROAD AREA OF 850 MB RELATIVE VORTICITY FROM 07-11N
BETWEEN 29W-41W. ISOLATED MODERATE CONVECTION IS FROM 05N-10N
BETWEEN 34W-41W.

TROPICAL WAVE EXTENDS FROM 07N49W TO 14N48W MOVING W AT 15 KT.
THE WAVE APPEARS AS PART OF A GREATER 700 MB TROUGH BETWEEN 46W-
59W...OF WHICH THE WEAKER 700 MB TROUGH IS ALONG 49W. CONVECTION
REMAINS VERY LIMITED WITH ONLY ISOLATED MODERATE CONVECTION FROM
09N-10N BETWEEN 46W-48W.

TROPICAL WAVE EXTENDS FROM 10N56W TO 19N54W MOVING W AT 15 KT.
SIMILAR TO THE PRIOR WAVE...THE WAVE IS A PART OF A LARGER 700
MB TROUGH ALOFT BETWEEN 46W-59W. IT IS LIKELY ENERGY FROM BOTH
THESE WAVE WILL MERGE OVER THE NEXT SEVERAL DAYS. NO SIGNIFICANT
DEEP CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 15N86W TO 22N84W MOVING W AT 15 KT.
THE WAVE CONTINUES TO MOVE ON THE SOUTHERN PERIPHERY OF A MID-
LEVEL RIDGE CENTERED OVER THE YUCATAN CHANNEL REGION WITH MOST
OF THE LOW-LEVEL ENERGY FOCUSED OVER CENTRAL AMERICA AND AREAS
OF THE EAST PACIFIC SOUTH OF NICARAGUA. NO SIGNIFICANT DEEP
CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE COAST OF AFRICA NEAR 11N20W
TO 10N27W TO 09N32W. THE INTERTROPICAL CONVERGENCE ZONE AXIS
EXTENDS FROM 07N37W TO 07N41W TO 06N49W TO 08N55W. ASIDE FROM
CONVECTION ASSOCIATED WITH THE PREVIOUSLY MENTIONED TROPICAL
WAVES...ISOLATED MODERATE CONVECTION IS FROM 07N-12N BETWEEN 20W-
33W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 05N-08N
BETWEEN 38W-42W...AND FROM 06N-09N BETWEEN 50W-56W.

...DISCUSSION...

GULF OF MEXICO...
A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH COVERS MUCH OF THE
EASTERN CONUS WITH A TROUGH AXIS DIPPING SOUTHWARD OVER PORTIONS
OF THE NE GULF. AS OF 17/0300 UTC...THE TROUGHING SUPPORTS A
COLD FRONT EXTENDING FROM THE FLORIDA PANHANDLE NEAR 31N84W W-SW
TO THE MISSISSIPPI RIVER DELTA REGION NEAR 29N90W. FROM THERE
THE FRONT BECOMES STATIONARY ACROSS COASTAL LOUISIANA TO THE
TEXAS AND LOUISIANA BORDER. IN ADDITION...A PRE-FRONTAL SURFACE
TROUGH IS ANALYZED FROM NEAR JACKSONVILLE FLORIDA SW TO 28N87W
IN THE NE GULF WATERS. WHILE THERE IS RELATIVELY DRY CONDITIONS
ALONG THE FRONT...A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING
ALONG THE FLORIDA COAST AND INLAND PORTIONS OF THE PENINSULA
FROM 28N-29N BETWEEN 81W-84W. OTHER ISOLATED SHOWERS ARE
OCCURRING FROM 25N-27N EAST OF 85W. OTHERWISE...A SURFACE RIDGE
AXIS EXTENDS FROM ACROSS CUBA ALONG 22N INTO THE CENTRAL GULF
THEN SW TO A 1016 MB HIGH ANCHORED ALONG THE MEXICO COAST NEAR
20N97W. MOSTLY CLEAR SKIES PREVAIL IN ASSOCIATION WITH THE
SURFACE RIDGE WHICH IS FORECAST TO SHIFT EASTWARD THROUGH EARLY
FRIDAY. BY FRIDAY...SOUTHERLY RETURN FLOW WILL HAVE ESTABLISHED
ITSELF ACROSS THE WESTERN GULF AS AN AREA OF LOW PRESSURE
DEVELOPS ACROSS THE INTERMOUNTAIN WEST.

CARIBBEAN SEA...
NORTHWESTERLY FLOW ALOFT PREVAILS OVER THE WESTERN CARIBBEAN W
OF 76W THIS EVENING PROVIDING MOSTLY STABLE CONDITIONS AT THE
SURFACE. HOWEVER...A PORTION OF UPPER LEVEL TROUGHING EXTENDS
FROM THE SW NORTH ATLC OVER CUBA AND THE WINDWARD PASSAGE REGION
GENERATING AN AREA OF SCATTERED SHOWERS AND TSTMS N OF 18N
BETWEEN 74W-80W. OTHER ISOLATED SHOWERS AND TSTMS ARE NOTED ON
SATELLITE IMAGERY ACROSS WESTERN CUBA AND THE ADJACENT COASTAL
WATERS N OF 21N. FARTHER EAST...A BROAD UPPER LEVEL TROUGH IS
OVER THE CENTRAL CARIBBEAN BETWEEN 70W-76W THAT REMAINS FAIRLY
STABLE WITH WATER VAPOR IMAGERY INDICATING DRY AIR ALOFT. WEST-
SOUTHWESTERLY FLOW ALOFT RESUMES E OF 70W ON THE SOUTHERN
PERIPHERY OF THE UPPER LEVEL TROUGH WITH MOSTLY CLEAR SKIES
PREVAILING THIS EVENING ACROSS PUERTO RICO...THE US/UK VIRGIN
ISLANDS...AND THE REMAINDER OF THE LESSER ANTILLES. MODERATE TO
FRESH TRADES ARE EXPECTED TO PERSIST THROUGH SATURDAY.

...HISPANIOLA...
CURRENTLY CONDITIONS REMAIN FAIRLY TRANQUIL AND THIS IS EXPECTED
THROUGH THE OVERNIGHT PERIOD. UPPER LEVEL TROUGHING LIES TO THE
WEST OF THE ISLAND GENERATING SCATTERED SHOWERS AND TSTMS ACROSS
EASTERN CUBA...HOWEVER MUCH OF THIS ACTIVITY SHOULD REMAIN W OF
THE ISLAND. GIVEN LITTLE MOVEMENT OF THE UPPER LEVEL LOW AND
ASSOCIATED TROUGH TO THE NORTH OVER THE SW NORTH ATLC...AN UPPER
LEVEL DIFFLUENT ENVIRONMENT REMAINS ACROSS HISPANIOLA AND
SCATTERED SHOWERS AND TSTMS ARE EXPECTED THURSDAY AFTERNOON AND
EVENING WITH PEAK DAYTIME HEATING AND INSTABILITY.

ATLANTIC OCEAN...
A LONGWAVE MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR
IMAGERY OVER THE EASTERN CONUS THAT SUPPORTS A 1010 MB LOW
CENTERED ACROSS SOUTH CAROLINA NEAR 34N80W. THE FRONTAL BOUNDARY
ASSOCIATED WITH THE LOW REMAINS INLAND ALONG THE COAST...WITH
MOSTLY SOUTHWESTERLY WINDS ALOFT AND AT THE SURFACE ADVECTING
MOISTURE AND CLOUDINESS NORTHWARD THIS EVENING. ISOLATED SHOWERS
AND TSTMS ARE OCCURRING EAST OF THE FRONT N OF 29N BETWEEN 73W-
80W. FARTHER SOUTH...MOISTURE ON THE WESTERN PERIPHERY OF AN
ELONGATED UPPER LEVEL LOW CENTERED NEAR 26N72W IS GENERATING
SCATTERED SHOWERS AND TSTMS FROM 18N-27N BETWEEN 73W-79W. ON THE
EASTERN PERIPHERY OF THE UPPER LEVEL LOW...SCATTERED SHOWERS AND
TSTMS ARE OCCURRING FROM 24N-30N BETWEEN 64W-71W. FARTHER
EAST...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER
THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1031 MB HIGH
CENTERED NEAR 36N53W.

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

$$
HUFFMAN



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