[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 191038
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 19 2015

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.

...TROPICAL WAVES...
TROPICAL WAVE EXTENDS FROM 04N36W TO 16N35W MOVING W AT 20-25
KT. THE WAVE COINCIDES WITH A BROAD 700 MB TROUGH BETWEEN 32W-
39W. SSMI TPW IMAGERY INDICATES MODERATE MOISTURE S OF 11N ALONG
THE WAVE. SCATTERED MODERATE CONVECTION IS FROM 04N-08N BETWEEN
36W-42W.

TROPICAL WAVE EXTENDS FROM 07N50W TO 19N49W MOVING W AT 20 KT.
THIS WAVE COINCIDES WITH A BROAD 700 MB TROUGH BETWEEN 46W-52W.
SSMI TPW IMAGERY INDICATES A POLEWARD SURGE OF HIGH MOISTURE
ALONG THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 09N-
13N BETWEEN 49W-53W.

TROPICAL WAVE EXTENDS FROM 09N60W TO 19N57W MOVING W AT 15-20
KT. THE WAVE COINCIDES WITH A TILTED 700 MB TROUGH BETWEEN 55W-
61W. BUOY 41300 REPORTED A WIND SHIFT FROM THE ENE TO ESE AS THE
WAVE PASSED THE AREA THIS MORNING. DRY AIR AND SAHARAN DUST IS
EVIDENT IN THE ENVIRONMENT OF THE WAVE...INHIBITING CONVECTION
ALONG THE WAVE.

TROPICAL WAVE HAS MOVED INLAND OVER THE YUCATAN TO GUATEMALA AND
OVER THE EASTERN PACIFIC. PLEASE REFER TO THE PACIFIC TROPICAL
WEATHER DISCUSSION AT MIATWOEP FOR ADDITIONAL DETAILS.

...ITCZ/MONSOON TROUGH...
THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N38W TO
05N53W. ASIDE FROM CONVECTION ASSOCIATED WITH THE EASTERNMOST
TROPICAL WAVE...WIDELY SCATTERED MODERATE CONVECTION IS FROM THE
EQUATOR TO 07N BETWEEN 44W AND 49W.

...DISCUSSION...

GULF OF MEXICO...
NORTHEASTERLY FLOW ALOFT PERSISTS ACROSS THE MAJORITY OF THE
GULF AROUND RIDGING THAT EXTENDS FROM THE TX COAST TO THE TN
VALLEY. A WEAKNESS IN THIS RIDGE OVER THE NE GULF CONTINUES TO
SUPPORT A SURFACE TROUGH THAT EXTENDS FROM THE FL BIG BEND NEAR
30N84W TO 27N88W. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ARE OCCURRING WITHIN 125 NM OF THE TROUGH AXIS. ADDITIONAL
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OVER THE SE
GULF FROM 23N TO 27N E OF 87W AND ARE PRIMARILY BEING DRIVEN BY
WEAK DISTURBANCES IN THE NE FLOW ALOFT COMBINED WITH DEEP
TROPICAL MOISTURE IN PLACE ACROSS THE AREA. SURFACE RIDGING
ANCHORED BY A 1018 MB HIGH CENTERED NEAR 27N92W SUPPORTS
GENERALLY FAIR WEATHER ACROSS THE REMAINDER OF THE GULF BASIN. A
DIURNALLY DRIVEN SURFACE TROUGH EXTENDS FROM 22N93W TO 18N94W.
CURRENTLY THERE IS NO DEEP CONVECTION NOTED WITH THIS TROUGH.
OVER THE NEXT 24 HOURS SURFACE TROUGHING IS EXPECTED TO PERSIST
OVER THE NE GULF WITH ONGOING CONVECTION POSSIBLE OVER THAT
PORTION OF THE BASIN.

CARIBBEAN SEA...
NORTHEASTERLY FLOW ALOFT COVERS THE NW CARIBBEAN AROUND THE
PERIPHERY OF THE TX UPPER LEVEL RIDGE...WITH S TO SE FLOW ALOFT
OVER THE EASTERN CARIBBEAN AROUND A CENTRAL TROPICAL ATLC UPPER
LEVEL RIDGE. IN BETWEEN...TROUGHING THAT EXTENDS FROM THE W ATLC
TO THE SW CARIBBEAN SUPPORTS A BROAD AREA OF WEAK UPPER LEVEL
DIFFLUENCE THAT SPANS FROM CUBA AND HISPANIOLA SW TO NICARAGUA
AND THE SW CARIBBEAN. THIS DIFFLUENCE COMBINED WITH MODERATE TO
HIGH ATMOSPHERIC MOISTURE SUPPORTS SCATTERED THUNDERSTORMS FROM
15N TO 23N BETWEEN 74W AND 86W...INCLUDING THE CAYMAN ISLANDS
AND THE COASTS OF NICARAGUA AND HONDURAS. SCATTERED MODERATE
CONVECTION IS S OF 13N W OF 76W OVER THE SW CARIBBEAN. 15 TO 20
KT TRADE WINDS COVER THE MAJORITY OF THE CARIBBEAN WITH A SMALL
AREA OF WINDS TO 25 KT N OF THE COLOMBIA COAST...WHERE THE
PRESSURE GRADIENT IS TIGHTEST BETWEEN ATLC HIGH PRESSURE AND
LOWER PRESSURE OVER COLOMBIA. OVER THE NEXT 24 HOURS CONVECTION
WILL BE POSSIBLE OVER THE SW AND WESTERN CARIBBEAN UNDER
DIFFLUENT FLOW IN THE PRESENCE OF DEEP MOISTURE.

...HISPANIOLA...
DRY AIR IN PLACE IS EXPECTED TO INHIBIT SHOWER AND THUNDERSTORMS
OVER THE ISLAND TODAY...EXCEPT FOR ISOLATED SHOWERS IN SHALLOW
MOISTURE IN THE TRADE WIND FLOW. SIMILAR CONDITIONS WILL OCCUR
ON MONDAY.

ATLANTIC OCEAN...
UPPER LEVEL RIDGING EXTENDS FROM THE US INTO THE W ATLC WITH MID
TO UPPER LEVEL DISTURBANCES EVIDENT IN WATER VAPOR IMAGERY
ROUNDING THE PERIPHERY OF THE RIDGING W OF 75W AROUND
30N...SUPPORTING WIDELY SCATTERED MODERATE CONVECTION FROM 28N
TO 31N BETWEEN 70W AND 78W. A PAIR OF UPPER LOWS CENTERED NEAR
28N68W AND 29N57W SUPPORT ISOLATED THUNDERSTORMS N OF 24N
BETWEEN 54W AND 68W. A SURFACE TROUGH IS A REFLECTION OF THE
EASTERNMOST UPPER LOW AND EXTENDS FROM 29N56W TO 25N66W. THIS
TROUGH ALSO ACTS AS A WEAKNESS IN THE SUBTROPICAL RIDGE WITH A
1020 MB HIGH CENTERED NEAR 28N67W. A 1024 MB HIGH CENTERED NEAR
29N41W ANCHORS RIDGING THAT EXTENDS ACROSS THE CENTRAL AND
EASTERN SUBTROPICAL ATLC. THREE TROPICAL WAVES ARE OVER THE
TROPICAL NORTHERN ATLC. PLEASE REFER TO THE TROPICAL WAVES
SECTION FOR MORE DETAILS. EXPECT CONVECTION TO CONTINUE ALONG
30N OFF THE FL COAST OVER THE NEXT 24 HOURS.

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

$$
LATTO
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