[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 06 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1745 UTC.

...SPECIAL FEATURES...

THE CENTER OF POST-TROPICAL STORM BERTHA IS NEAR 40.2N 62.7W AT
06/1500 UTC OR 267 NM S OF HALIFAX NOVA SCOTIA. BERTHA IS MOVING
TOWARD THE NORTHEAST AT 27 KT. THE ESTIMATED MINIMUM CENTRAL
PRESSURE IS 1006 MB. MAXIMUM SUSTAINED WINDS ARE 45 KT WITH
GUSTS TO 55 KT. SCATTERED MODERATE CONVECTION IS EAST OF THE
STORM CENTER N OF 36N BETWEEN 60W-64W. PLEASE READ THE LATEST
NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT3/WTNT33
KNHC AND THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS
MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS.

...TROPICAL WAVES...

TROPICAL WAVE IS JUST WEST OF THE CAPE VERDE ISLANDS WITH AXIS
EXTENDING FROM 19N25W TO 11N26W MOVING W AT 5 KT. THE METEOSAT
SAL TRACKING IMAGERY SHOW THE WAVE IS BEING ENGULFED BY DRY
AIR...HOWEVER DISTANT ENOUGH TO ALLOW A MODERATE DEEP LAYER
MOISTURE IN ITS ENVIRONMENT. THE PRESENCE OF SAHARAN DUST IN THE
WAVE ENVIRONMENT OBSERVED IN THE PSEUDO NATURAL COLOR METEOSAT
IMAGERY AS WELL AS THE LACK OF A LIFTING MECHANISM ARE POSSIBLE
FACTORS FOR THE LACK OF CONVECTION AT THE TIME.

A FORMER SURFACE TROUGH IS NOW BEING ANALYZED AS A TROPICAL WAVE
ALONG 51W JUST WEST OF THE ITCZ. SAHARAN DRY AIR IS IN THE
NORTHERN WAVE ENVIRONMENT...THUS LIMITING CONVECTION N OF 13N. A
DEEP LAYER MOIST ENVIRONMENT AND UPPER LEVEL DIFFLUENCE SUPPORT
SCATTERED SHOWERS AND ISOLATED TSTMS FROM 10N-13N BETWEEN 47W-
53W.

TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS EXTENDING
FROM 22N68W TO 11N70W MOVING W AT 15 KT. ISOLATED SHOWERS WITHIN
120-180 NM E OF THE WAVE AXIS. DEEP LAYER MOISTURE ENHANCES
ISOLATED SHOWERS AND TSTMS FROM 16N-19N BETWEEN 68W-71W.

TROPICAL WAVE IS ENTERING CENTRAL AMERICA WITH AXIS EXTENDING
FROM 18N83W TO 9N82W MOVING WEST AT 15-20 KT. AN UPPER-LEVEL
INVERTED TROUGH IN THAT REGION SUPPORT THE WAVE AND SMALL
CLUSTERS OF MODERATE CONVECTION AND TSTMS S OF 15N W OF 81W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE WEST COAST OF AFRICA NEAR
12N16W TO 10N26W TO 8N35W. THE ITCZ BEGINS NEAR 8N35W AND
CONTINUES ALONG 8N42W TO 10N50W. SCATTERED MODERATE CONVECTION
IS FROM 9N-15N E OF 20W...FROM 5N-10N BETWEEN 20W-37W AND FROM
9N-12N BETWEEN 53W-59W.

...DISCUSSION...

THE GULF OF MEXICO...

THE WESTERN PERIPHERY OF A MIDDLE TO UPPER LEVEL RIDGE OVER THE
EASTERN GULF IS SUPPORTING A 1019 MB HIGH NEAR 27N86W.
ANTICYCLONIC WIND OF 5 KT ASSOCIATED WITH THIS HIGH IS ADVECTING
LOW LEVEL MOISTURE INTO THE BASIN FROM THE ENVIRONMENT OF A
SURFACE TROUGH EXTENDING ACROSS THE SW N ATLC TO THE FLORIDA
STRAITS. THIS MOISTURE IS SUPPORTING CLOUDINESS AND ENHANCING
ISOLATED SHOWERS E OF 90W. OVER THE SW GULF...AN UPPER LEVEL LOW
SUPPORT SCATTERED SHOWERS AND TSTMS OVER THE WESTERN BAY OF
CAMPECHE W OF 93W. OTHERWISE...SURFACE RIDGING WILL PREVAIL
ACROSS GREAT PORTIONS OF THE GULF DURING THE NEXT TWO DAYS. A
TROPICAL WAVE IS FORECAST TO APPROACH THE SE GULF BY WED MORNING.

THE CARIBBEAN SEA...

TWO UPPER LEVEL INVERTED TROUGHS SUPPORT TWO TROPICAL WAVES IN THE
BASIN...ONE MOVING ACROSS CENTRAL AMERICA AND THE OTHER ACROSS
THE CENTRAL BASIN. THE WESTERNMOST WAVE IS SUPPORTING SCATTERED
MODERATE CONVECTION AND TSTMS WITHIN 100 NM OF THE COASTLINE
FROM NICARAGUA TO PANAMA W OF 80W. THE AXIS OF THE SECOND TROPICAL
WAVE IS MOVING ACROSS EASTERN DOMINICAN REPUBLIC WHERE IS
ENHANCING SHOWERS AND TSTMS. THIS SHOWER ACTIVITY EXTENDS
SOUTHWARD TO 15N AND EASTWARD TO WESTERN PUERTO RICO. SEE THE
TROPICAL WAVES SECTION FOR MORE DETAILS. FAIR WEATHER IS ELSEWHERE
BEING SUPPORTED BY DRY AIR SUBSIDENCE FROM ALOFT. TRADES OF 10-
15 KT DOMINATE ACROSS THE CARIBBEAN WITH ASCAT DATA INDICATING A
MAXIMUM OF 20 KT WINDS ALONG THE COAST OF COLOMBIA. THE TROPICAL
WAVE CURRENTLY OVER THE CENTRAL BASIN IS FORECAST TO MOVE W-NW
AND INTO THE SE GULF BY WED MORNING. THE NEXT TROPICAL WAVE WILL BE
ENTERING THE EASTERN CARIBBEAN THU MORNING.

...HISPANIOLA...

A TROPICAL WAVE IS MOVING ACROSS THE ISLAND AND ENHANCES ISOLATED
HEAVY SHOWERS AND TSTMS OVER DOMINICAN REPUBLIC AND SW HAITI.
ISOLATED SHOWERS EXTEND TO THE ISLAND SOUTHERN COASTAL WATERS.
MORE SHOWERS ARE ANTICIPATED AS THE WAVE CONTINUES A WESTWARD
PATH DURING THE NEXT 24 HOURS. WEATHER CONDITIONS IMPROVE ON THU
AFTERNOON.

THE ATLANTIC OCEAN...

A BROAD MIDDLE LEVEL TROUGH EXTENDING ACROSS THE EASTERN CONUS
AND THE FAR WESTERN ATLC CONTINUES TO SUPPORT A SURFACE TROUGH
EXTENDING FROM 30N73W TO 28N75W TO 24N81W WHICH IS ENHANCING
SCATTERED MODERATE CONVECTION N OF 25N BETWEEN 70W-79W. A HIGH
AMPLITUDE TROPICAL WAVE IS MOVING ACROSS HISPANIOLA WITH AXIS
EXTENDING NORTHWARD ABOUT 120 NM E OF THE SOUTHERN BAHAMAS. THIS
WAVE IS ENHANCING ISOLATED SHOWERS S OF 23N BETWEEN 66W-71W.
FARTHER EAST OVER THE CENTRAL ATLC...A MIDDLE TO UPPER LEVEL LOW
REFLECTS AS A SURFACE TROUGH ALONG 29N49W TO 25N52W WHICH IS
ENHANCING ISOLATED SHOWERS AND TSTMS WITHIN 60 NM OF THE AXIS.
OTHERWISE...A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH NEAR
34N27W DOMINATES ELSEWHERE N OF 21N.

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

$$
NR


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