Tropical Weather Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AXPZ20 KNHC 281000
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUL 28 2015

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0900 UTC.

...SPECIAL FEATURE...

TROPICAL DEPRESSION EIGHT-E WAS NEAR 16.2N 128.0W 1007 MB AT
0900 UTC JUL 28 MOVING WNW OR 290 DEG AT 11 KT. MAXIMUM
SUSTAINED WINDS 30 KT GUSTS 40 KT. UPPER LEVEL NW WIND SHEAR HAS
DECREASED SLIGHTLY IN THE PAST FEW HOURS...AND DEEP CONVECTION
HAS INCREASED ACROSS THE CENTER...WITH NUMEROUS MODERATE TO
STRONG CONVECTION OCCURRING WITHIN 90 NM E AND 30 NM W
SEMICIRCLES...WHILE BANDS OF SCATTERED MODERATE TO STRONG
CONVECTION WERE ELSEWHERE WITHIN 300 NM ACROSS THE E SEMICIRCLE.
THE SYSTEM IS EXPECTED TO STRENGTHEN SLIGHTLY TODAY AS IT
CONTINUES MOVING W-NW...BECOMING A TROPICAL STORM...THEN  WEAKEN
BACK A TROPICAL DEPRESSION ON WED. SEE THE LATEST NHC
FORECAST/ADVISORY UNDER AWIPS/WMO HEADER MIATCMEP3/WTPZ23 KNHC
FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE WAS INVOF 82W-83W MOVING W NEAR 10 KT. THE NORTH
PORTION OF THIS WAVE HAS SHIFTED MORE W-NW ACROSS CENTRAL
AMERICA. CONVECTION IN THIS AREA WAS ALSO ASSOCIATED WITH THE
MONSOON TROUGH AND A TUTT OVERHEAD ALONG 04N-05N...AND IS
DESCRIBED BELOW.

A TROPICAL WAVE WAS INVOF 109W-111W MOVING W 15-20 KT. ISOLATED
TO SCATTERED MODERATE TO STRONG CONVECTION WAS WITHIN 60 NM E
AND 180 NM W OF THE WAVE FROM 04N-13N.

BROAD LOW PRES NEAR 08.5N116.5W 1008 MB WAS EMBEDDED WITHIN THE
MONSOON TROUGH...AND ALSO ASSOCIATED WITH A TROPICAL
WAVE...MOVING W 15-20 KT. BANDS AND LINES OF SCATTERED MODERATE
TO STRONG CONVECTION WERE OCCURRING AROUND THE PERIPHERY OF THIS
CIRCULATION...WITHIN 270 NM ACROSS THE NE AND 300 NM SW
SEMICIRCLES. THIS LOW PRES AREA HAS THE POTENTIAL TO GRADUALLY
BECOME BETTER ORGANIZED OVER THE NEXT SEVERAL DAYS AS IT
CONTINUES MOVING W.

A TROPICAL WAVE WAS INVOF 132W-135W MOVING W AROUND 15 KT.
SCATTERED MODERATE TO STRONG CONVECTION WAS FROM 09N TO 14N
BETWEEN 133W AND 139W.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM 06.5N78W TO 09N85W TO 07.5N94W
TO LOW PRES NEAR 08.5N116.5W TO 10N120W...WHERE IT IS
FRACTURED...THEN RESUMES FROM 13N129W TO BEYOND LOW PRES NEAR
10N140.5W. SCATTERED MODERATE TO STRONG CONVECTION WITHIN 120 NM
N AND 300 NM S OF TROUGH E OF 90W...AND WITHIN 120 NM N AND 240
NM S OF TROUGH BETWEEN 90W AND 112W.

...DISCUSSION...

1029 MB HIGH PRESSURE IS ANALYZED WELL N OF THE AREA NEAR
44N136W AND EXTENDS A RIDGE AXIS SE THROUGH 30N130W TO
19N114W...AND OVER THE WATERS OFF THE BAJA CALIFORNIA PENINSULA.
DEEP-LAYERED TROUGHING OVER THE SW UNITED STATES AND A MID-LEVEL
CYCLONE MEANDERING ACROSS S CENTRAL BAJA CALIFORNIA HAVE FORCED
MORE TROUGHING AT THE SURFACE. THIS INCREASED THE PRESSURE
GRADIENT AND THE WINDS OFFSHORE OF THE BAJA CALIFORNIA PENINSULA
LATE THIS AFTERNOON AND EVENING...AND HAS BEGUN TO DIMINISH
SLIGHTLY EARLY THIS MORNING. THESE MODERATE TO FRESH NW WINDS ARE
FORECAST TO CONTINUE TO DIMINISH THIS MORNING TO 20 KT OR LESS.
THE PRESSURE GRADIENT WILL SLACKEN FURTHER DURING THE DAY
TODAY WHEN THE AFOREMENTIONED TROUGHING WEAKENS.

THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL RIDGE AND LOWER
PRESSURE ALONG THE MONSOON TROUGH HAS BROUGHT MODERATE TO FRESH
TRADE WINDS TO THE AREA PRIMARILY N OF 10N W OF 125W. THE AREA
OF STRONGEST TRADES CLOSEST TO THE TYPICAL CONVERGENCE ZONE S OF
20N IS FORECAST TO SHIFT W OF THE AREA OVER THE NEXT TWO DAYS AS
TROPICAL DEPRESSION EIGHT-E MOVES W-NW...SHIFTING THE STRONGEST
PRESSURE GRADIENT W. SEAS WERE 7-9 FT IN NE WIND WAVES AND MIXED
SE AND SW SWELL PRIMARILY FROM 07N TO 16N W OF 134W. THESE
MARINE CONDITIONS SHOULD SUBSIDE BELOW 8 FT BY THIS AFTERNOON.

GAP WINDS...
GULF OF PAPAGAYO...ENHANCED TRADE WINDS FROM THE SOUTHERN
CARIBBEAN ARE BLOWING ACROSS CENTRAL AMERICA AND FUNNELING
THROUGH MOUNTAINOUS PASSAGES CENTRAL AMERICA. OFFSHORE NE WINDS
ARE BRIEFLY PULSING TO 20-25 KT WITH THE ASSISTANCE OF NOCTURNAL
DRAINAGE FLOW ACROSS AND DOWNWIND OF PAPAGAYO EARLY THIS MORNING
AND WILL DO SO AGAIN TONIGHT...WITH SEAS BUILDING TO 9 FT.

$$
STRIPLING


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.