Tropical Weather Discussion
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000
AXNT20 KNHC 201103
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED AUG 20 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 1009 MB LOW IS CENTERED NEAR 10N53W AND REMAINS EMBEDDED
WITHIN LOW-LEVEL CYCLONIC MONSOONAL FLOW ACROSS THE TROPICAL
ATLC. A TROPICAL WAVE TO THE EAST-NORTHEAST OF THE LOW IS
EXPECTED TO INJECT ENERGY INTO THE LOW DURING THE NEXT 24 TO 48
HOURS WITH MOST GLOBAL MODELS SUGGESTING DEVELOPMENT OF THE
SURFACE LOW THAT TRACKS W-NW TOWARD THE LEEWARD ISLANDS AND NE
CARIBBEAN BY FRIDAY. WIDELY SCATTERED MODERATE CONVECTION IS
FROM 06N-12N BETWEEN 51W-57W.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 16N19W TO 24N19W MOVING W AT 10-15
KT. THE WAVE HAS EMERGED OFF THE WEST AFRICAN COAST DURING THE
PAST 12 HOURS AND COINCIDES WITH AN AMPLIFIED 700 MB TROUGH
BETWEEN 16W-24W AND 850 MB RELATIVE VORTICITY FOCUSED IN THE
VICINITY OF 14N21W WITHIN THE MONSOON TROUGH AXIS AND IN
VICINITY OF A 1013 MB LOW ALONG THE WAVE AXIS NEAR 21N. NO
SIGNIFICANT CONVECTION IS NOTED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 13N45W TO 23N51W MOVING W AT 20 KT.
THE WAVE COINCIDES WITH 700 MB TROUGHING ALOFT AND A MAXIMUM IN
850 MB RELATIVE VORTICITY NOTED ALONG THE MONSOON TROUGH AXIS
BETWEEN 40W AND 50W. NO SIGNIFICANT CONVECTION IS OCCURRING WITH
THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 10N59W TO 21N61W MOVING W AT 20 KT.
700 MB TROUGHING ASSOCIATED WITH THE WAVE HAS LIKELY MERGED WITH
MID-LATITUDE 700 MB TROUGHING OVER THE CENTRAL ATLC...HOWEVER
RESIDUAL ENERGY CONTINUES TO MOVE WEST OF THE 1009 MB SPECIAL
FEATURES LOW EMBEDDED WITHIN THE MONSOON TROUGH NEAR 10N53W. NO
SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME.

TROPICAL WAVE EXTENDS FROM 08N93W TO 19N95W MOVING W AT 20 KT.
MOST OF THE ENERGY ASSOCIATED WITH THIS WAVE LIES IN THE EAST
PACIFIC REGION...HOWEVER 850 MB RELATIVE VORTICITY FIELDS REMAIN
MAXIMIZED ACROSS PORTIONS OF SOUTHERN MEXICO AND GUATEMALA THAT
CONTINUE TO SUPPORT ISOLATED MODERATE TO STRONG CONVECTION FROM
14N-19N BETWEEN 93W-98W.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO
13N26W TO 15N39W TO A 1009 MB LOW PRES NEAR 10N53W TO 08N59W.
ISOLATED MODERATE CONVECTION IS FROM 12N-15N BETWEEN 25W-28W...
AND FROM 08N-13N BETWEEN 43W-51W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL LOW IS CENTERED NEAR 23N97W THAT INFLUENCES MUCH
OF THE WESTERN GULF W OF 90W WITH MOIST SOUTH-SOUTHWESTERLY FLOW
ALOFT. WHILE SURFACE RIDGING EXTENDS ALONG 28N ACROSS THE
BASIN...DYNAMICS ASSOCIATED WITH THE UPPER LEVEL LOW IS
ADVECTING MOISTURE NORTHWARD AND GENERATING WIDELY SCATTERED
SHOWERS AND ISOLATED TSTMS ACROSS THE NW GULF WATERS FROM 24N-
28N BETWEEN 91W-96W. ELSEWHERE...THE SURFACE RIDGE EXTENDING
FROM THE SW NORTH ATLC IS PROVIDING FOR OVERALL FAIR CONDITIONS
AND MOSTLY CLEAR SKIES ACROSS THE EASTERN GULF THIS MORNING. A
FEW ISOLATED SHOWERS AND TSTMS ARE NOTED FROM 24N-26N BETWEEN
82W-96W DUE TO WEAK LOW-LEVEL MOISTURE CONVERGENCE AND WEAK
MIDDLE TO UPPER LEVEL SOUTHWESTERLY FLOW ALOFT ON THE WESTERN
PERIPHERY OF AN UPPER LEVEL ANTICYCLONE CENTERED OVER THE
SOUTHERN FLORIDA PENINSULA NEAR 26N81W. THE SURFACE RIDGE IS
EXPECTED TO REMAIN ANCHORED ALONG 28N/29N THROUGH SUNDAY WITH
GENTLE TO MODERATE EAST WINDS.

CARIBBEAN SEA...
A MAJORITY OF THE CARIBBEAN IS UNDER THE INFLUENCE OF DRY UPPER
LEVEL CYCLONIC CIRCULATIONS ALOFT...ONE CENTERED OVER THE NW
CARIBBEAN NEAR 19N82W AND THE OTHER CENTERED NEAR 22N64W THAT
EXTENDS UPPER LEVEL TROUGHING OVER MUCH OF THE EASTERN CARIBBEAN
E OF 72W. WATER VAPOR IMAGERY CONFIRMS THE DRY AIR ALOFT AND
THIS IS PROVIDING FOR OVERALL STABLE CONDITIONS THIS MORNING...
HOWEVER ISOLATED SHOWERS ARE OCCURRING ACROSS THE NE CARIBBEAN N
OF 16N BETWEEN 63W-71W. THE AREA OF LOW-LEVEL MOISTURE ACROSS
THE NE CARIBBEAN HAS CONTINUED TO MOVE WEST-SOUTHWESTWARD DURING
THE PAST 24 HOURS AS A TROPICAL WAVE APPROACHES FROM THE EAST.
OTHERWISE...SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE
SW CARIBBEAN IN AN AREA OF MAXIMUM LOW-LEVEL MOISTURE
CONVERGENCE AND WITHIN CLOSE PROXIMITY TO THE MONSOON TROUGH
AXIS ALONG 09N/10N. MODERATE TO FRESH TRADES ARE EXPECTED TO
PERSIST GENERALLY S OF 17N BETWEEN 68W-80W.

...HISPANIOLA...
CURRENTLY...ISOLATED SHOWER ACTIVITY CONTINUES ACROSS FAR
EASTERN PORTIONS OF THE ISLAND AND ADJACENT COASTAL WATERS IN
THE MONA PASSAGE WITH LOW-LEVEL MOISTURE COVERING A LARGE AREA
TO THE EAST ACROSS THE NE CARIBBEAN SEA FROM 16N-21N BETWEEN 63W-
71W. THE APPROACH OF A WEAK TROPICAL WAVE WILL ALSO IMPACT THE
ISLAND DURING THE NEXT 24 TO 48 HOURS WITH THE USUAL POSSIBILITY
OF AFTERNOON AND EVENING CONVECTION DUE TO PEAK DAYTIME HEATING
AND INSTABILITY.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL RIDGE IS ANCHORED OVER THE SW NORTH ATLC
NEAR 26N81W THAT EXTENDS AN AXIS NE TO 32N70W SUPPORTING SURFACE
RIDGING ACROSS MUCH OF THE SW NORTH ATLC W OF 60W. TO THE NORTH
OF THE SURFACE RIDGE AXIS ALONG 27N/28N...LOWER PRESSURE OFF THE
COAST OF THE DELMARVA EXTENDS WEAK SURFACE TROUGHING ALONG THE
EASTERN SEABOARD AS A SURFACE TROUGH ANALYZED FROM 27N81W TO
BEYOND 32N78W WITH ISOLATED SHOWERS AND TSTMS OCCURRING WITHIN
90 NM EITHER SIDE OF THE BOUNDARY N OF 28N. OTHERWISE...THE
REMAINDER OF THE SW NORTH ATLC REMAINS UNDER MOSTLY FAIR SKIES
AND CONDITIONS THIS MORNING. FARTHER EAST...THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC ARE ALSO UNDER THE INFLUENCE OF A
SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED SW OF THE
AZORES NEAR 34N35W.

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

$$
HUFFMAN


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