[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 271800
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED AUG 27 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...

HURRICANE CRISTOBAL IS CENTERED NEAR 31.8N 72.2W AT 27/1500 UTC
OR ABOUT 380 NM WEST OF BERMUDA...MOVING NORTHWARD AT 10 KT.
ESTIMATED MINIMUM CENTRAL PRESSURE IS 983 MB. MAXIMUM SUSTAINED
WINDS ARE 70 KT WITH GUSTS TO 85 KT. SCATTERED MODERATE
CONVECTION IS N OF 23N BETWEEN 67W-75W. LIGHTING DATA INDICATE
TSTMS FROM 23N-28N BETWEEN 70W-74W. SEE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS ON THE EASTERN ATLC WITH AXIS JUST WEST OF
THE CAPE VERDE ISLANDS EXTENDING FROM 20N24W TO 10N26W...MOVING
W AT 20 KT. SAHARAN DRY AIR AND DUST ARE IN THE WAVE ENVIRONMENT
WHICH IS HINDERING CONVECTION AT THE TIME.

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS EXTENDING
FROM 21N34W TO 11N34W MOVING W AT 20 KT. SAHARAN DRY AIR AND
DUST ARE IN THE WAVE ENVIRONMENT...THUS INHIBITING CONVECTIVE
ACTIVITY.

A TROPICAL WAVE IS ABOUT 200 NM EAST OF THE LESSER ANTILLES WITH
AXIS EXTENDING FROM 21N56W TO 10N57W...MOVING W AT 20-25 KT.
DEEP LAYER MOISTURE ACCOMPANIES THIS WAVE SOUTH OF 17N WHICH
ALONG WITH UPPER-LEVEL DIVERGENCE SUPPORT SCATTERED MODERATE
CONVECTION AND ISOLATED TSTMS FROM 11N-16N WEST OF 52W.

A TROPICAL WAVE IS ON THE CENTRAL CARIBBEAN WITH AXIS EXTENDING
FROM 19N68W TO 10N68W...MOVING WEST AT 20-25 KT. LOW-LEVEL
MOISTURE CONVERGENCE ALONG WITH UPPER-LEVEL DIVERGENCE IN THE
SOUTHERN REGION OF THE WAVE SUPPORT SCATTERED MODERATE
CONVECTION AND TSTMS S OF 15N EAST OF 71W.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W
AND CONTINUES ALONG 8N25W TO 11N40W. THE INTERTROPICAL
CONVERGENCE ZONE AXIS BEGINS NEAR 11N40W AND CONTINUES TO
12N51W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL
WAVES...SCATTERED MODERATE CONVECTION IS FROM 3N-9N BETWEEN 12W-
19W AND FROM 6N-9N BETWEEN 21W-28W.

...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE DOMINATES ACROSS THE GULF BEING SUPPORTED
BY A MIDDLE LEVEL INVERTED TROUGH ACROSS THE BASIN. A 1010 MB
LOW IS BEING ANALYZED IN THE NW GULF NEAR 27N94W FROM WHICH A
SURFACE TROUGH EXTENDS SE ALONG 25N90W TO COASTAL NORTHERN CUBA
NEAR 23N81W. LOW LEVEL MOISTURE CONVERGENCE ALONG THE TROUGH IS
ENHANCING ISOLATED SHOWERS AND TSTMS WITHIN 150 NM E-NE OF THE
AXIS. STRONG DEEP LAYER ENVIRONMENTAL WIND SHEAR ON THE NW GULF
IS KEEPING SCATTERED MODERATE CONVECTION NE OF THE LOW CENTER.
THIS CONVECTION IS LOCATED N OF 27N BETWEEN 91W-94W...AFFECTING
COASTAL SW LOUISIANA AND ADJACENT WATERS. ISOLATED SHOWERS AND
TSTMS ARE ON THE NW QUADRANT OF THE LOW WITHIN 120 NM OF THE
TEXAS COASTLINE. IN THE UPPER-LEVELS...AN ANTICYCLONIC
CIRCULATION IS NOTED IN WATER VAPOR IMAGERY SUPPORTING DRY AIR
SUBSIDENCE AND FAIR WEATHER ELSEWHERE IN THE GULF. A SURFACE
TROUGH IS ON THE EASTERN BAY OF CAMPECHE ALONG 22N90W TO 17N91W
WITH NO CONVECTION ASSOCIATED WITH IT. E-NE WIND FLOW OF 15-20
KT DOMINATE E OF THE SURFACE TROUGH WHILE N-NW WIND OF 5 KT IS
ON THE WESTERN SIDE OF IT. THE AREA OF LOW PRESSURE ON THE NW
GULF WILL MOVE SW INTO NE MEXICO BY THU MORNING. RAINSHOWERS
ASSOCIATED WITH THIS LOW ARE EXPECTED TO CONTINUE THROUGH
THURSDAY NIGHT.

CARIBBEAN SEA...

A MIDDLE TO UPPER LEVEL INVERTED TROUGH IS ON THE CENTRAL BASIN
SUPPORTING A BROAD AREA OF LOW PRESSURE ON THE SW CARIBBEAN
ASSOCIATED WITH A 1011 MB LOW NEAR 12N76W. THE MONSOON TROUGH
CONNECTS TO THIS LOW AND ENHANCE A CLUSTER OF MODERATE
CONVECTION AND TSTMS S OF 16N BETWEEN 75W-82W. ISOLATED SHOWERS
AND TSTMS ARE NOTED N OF 16N BETWEEN 76W-81W...INCLUDING JAMAICA
AND CENTRAL CUBA. AN ANTICYCLONIC CIRCULATION IS ON THE EASTERN
BASIN IN THE UPPER LEVELS CREATING A DIFFLUENT ENVIRONMENT ON
THE SE CARIBBEAN. THIS ENVIRONMENT ALOFT ALONG WITH LOW LEVEL
MOISTURE CONVERGENCE SUPPORT SCATTERED SHOWERS AND TSTMS
ASSOCIATED WITH A TROPICAL WAVE WITH AXIS ALONG 69W. THE PASSAGE OF
THE TROPICAL WAVE ALONG WITH A TIGHTER PRESSURE GRADIENT SUPPORT
TRADES OF 20 KT ACROSS THE CENTRAL AND EASTERN BASIN. SOUTHERLY-
SOUTHEASTERLY FLOW OF 5-15 KT DOMINATES ELSEWHERE. A NEW
TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN WATERS BY
THURSDAY MORNING SUPPORTING MORE RAINSHOWERS IN THE E-SE BASIN.

...HISPANIOLA...

MIDDLE TO LOWER LEVEL DRY AIR DOMINATE ACROSS THE ISLAND
SUPPORTING MAINLY FAIR WEATHER EARLY THIS AFTERNOON. A TROPICAL
WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN...HOWEVER THE
NORTHERN WAVE ENVIRONMENT IS DEVOID OF ABUNDANT MOISTURE. THE
PASSAGE OF THIS WAVE TODAY MAY ENHANCE ISOLATED SHOWERS THIS
EVENING BEING ENHANCED BY DAYTIME HEATING. A SECOND TROPICAL WAVE
WILL MOVE INTO THE EASTERN CARIBBEAN THU MORNING. THIS WAVE IS
ASSOCIATED WITH A BROAD AREA OF MOISTURE FORECAST TO PRODUCE
RAINSHOWERS MAINLY ACROSS THE SOUTHERN ISLAND THU THROUGH FRIDAY.

ATLANTIC OCEAN...

HURRICANE CRISTOBAL HAS MOVED NORTH OF THE AREA OF DISCUSSION
EARLIER THIS AFTERNOON. HOWEVER...ITS RAINBANDS CONTINUE TO
AFFECT THE SW N ATLC WATERS WITH SCATTERED MODERATE CONVECTION
AND TSTMS N OF 24N BETWEEN 68W-76W. SEE SPECIAL FEATURES SECTION
ABOVE. ISOLATED SHOWERS ARE ACROSS THE CENTRAL AND SOUTHERN
BAHAMAS AS WELL AS CUBA AND HISPANIOLA NORTHERN COASTAL WATERS.
OTHERWISE...BESIDES THE TROPICAL WAVES...THE REMAINDER OF THE
CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A BROAD
SURFACE RIDGE ANCHORED BY A 1025 MB HIGH CENTERED NEAR 31N48W
AND A PAIR OF HIGHS N OF 30N E OF 34W.

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

$$
NR


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