Hurricane Advisories Hurricane advisories

000
ABNT20 KNHC 161145
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT SAT JUL 16 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER STEWART

000
AXPZ20 KNHC 161011
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT JUL 16 2011

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
0915 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS FROM COASTAL COLOMBIA ALONG 10N WWD
ACROSS THE SW CARIBBEAN ALONG 10N TO LOW PRES 1008 MB NEAR
10.5N83W THEN MEANDERS NW ALONG PACIFIC COASTAL PORTIONS OF
CENTRAL AMERICA TO A SECOND LOW NEAR 15.5N95.5W 1007 MB THEN
CONTINUES NW ALONG THE MEXICAN NEAR SHORE COASTAL WATERS TO LOW
PRES NEAR 18.5N105W 1004 MB...THEN RESUMES IN BROAD CYCLONIC
FLOW FROM NEAR 16N110W TO 13N122W TO 10N131W WHERE IT
TRANSITIONS TO THE EPAC INTERTROPICAL CONVERGENCE ZONE AXIS TO
07.5N140W. SCATTERED MODERATE CONVECTION IS N OF 05N BETWEEN 82W
AND 86W. SCATTERED MODERATE TO STRONG CONVECTION WAS OCCURRING
ALONG AND WITHIN 120 NM S OF MONSOON TROUGH FROM 92W TO
106W...WITH SCATTERED MODERATE ISOLATED CONVECTION UP TO 240 NM
S OF AXIS BETWEEN 112W AND 130W. NO SIGNIFICANT CONVECTION NOTED
NEAR THE ITCZ AT THIS TIME.

...DISCUSSION...
A LONGWAVE UPPER LEVEL TROUGH IS REORGANIZING ACROSS THE PACIFIC
NORTHWEST COAST OF N AMERICA...AND EXTENDS SOUTHWARD INTO
DISCUSSION AREA TO A WEAKENING MID/UPPER LEVEL VORTEX AT 30N127W
WITH MID/UPPER LEVEL TROUGH EXTENDING SW TO NEAR 22N131W. BROAD
CYCLONIC FLOW ASSOCIATED WITH THIS TROUGH COVERS THE AREA N OF
22N W OF 118W...AND IS DOMINATED BY GENERAL CONVERGENCE ALOFT
AND SUBSIDENCE. TO THE SW...AN UPPER LEVEL ANTICYCLONE WAS
CENTERED JUST W OF THE AREA NEAR 22N146W AND CONTINUES TO DRIFT
WESTWARD.

A BROAD UPPER LEVEL ANTICYCLONE IS OVER THE CENTRAL CONUS THAT
INCLUDES MOST OF NORTHERN MEXICO AND THE SOUTHERN BAJA
CALIFORNIA/GULF OF CALIFORNIA REGION...AND CONTINUES TO ANCHOR A
BROAD UPPER LEVEL OMEGA BLOCK PATTERN STRADDLING N AMERICA N OF
30N. THIS BLOCKING PATTERN IS FORECAST TO MAINTAIN ITS GENERAL
POSITION THROUGH THE MIDDLE OF NEXT WEEK...LEAVING MID/UPPER
LEVEL TROUGHING ACROSS NW PORTIONS OF THE AREA. S OF THIS STRONG
RIDGE...AN UPPER LEVEL CYCLONE ACROSS THE WRN GULF OF MEXICO WAS
EMBEDDED IN THE PROGRESSIVE ELY FLOW ALOFT AND MOVING W TOWARD
CENTRAL MEXICO...AND IS FORECAST TO MOVE ACROSS MEXICO OVER THE
WEEKEND AND EXIT CENTRAL BAJA CALIFORNIA MON. S THROUGH SW OF
THESE UPPER LEVEL FEATURES...NE TO ELY UPPER LEVEL FLOW PREVAILS
AND CONTINUES TO PRODUCE A LIGHTLY SHEARED ENVIRONMENT CONDUCIVE
FOR VENTILATION OF DEEP CONVECTION ACROSS THE TROPICAL EPAC.

AT LOWER LEVELS...A WELL DEFINED AND ORGANIZED MONSOONAL
CIRCULATION CONTINUES IN THE LOWER TROPOSPHERE...CENTERED ON A
BROAD CYCLONIC CIRCULATION OFF THE SW COAST OF MEXICO NEAR
18N106W EXTENDING SE IN A GRADUALLY NARROWING ZONE ALONG COASTAL
CENTRAL AMERICA TO A CYCLONIC CIRCULATION STRADDLING COSTA RICA
AND ADJACENT AREAS OF NICARAGUA...PANAMA...AND THE FAR SW
CARIBBEAN. DEEP LAYERED MONSOONAL FLOW CONTINUES GENERALLY FROM
08N TO 15N BETWEEN 80W AND 115W...AND CONTINUES TO ABSORB
TROPICAL MOISTURE AND ENERGY FROM TROPICAL WAVE MOVING THROUGH
THE CARIBBEAN. DEEP CONVECTION WAS OCCURRING IN THIS BROAD ZONE
OF MONSOONAL FLOW FROM 06N TO 09N BETWEEN 81W AND 87W AND FROM
07N TO 12N BETWEEN 90W AND 102W. AT THE SURFACE...A MONSOONAL
TROUGH IS DESCRIBED ABOVE...WITH EMBEDDED LOWS INDICATED. TPW
PRODUCTS SHOW VERY HIGH MOISTURE VALUES IN EXCESS OF 2 INCHES
NEAR THE TROUGH AXIS ALONG THE MEXICAN COAST FROM NEAR
MANZANILLO TO THE GULF OF TEHUANTEPEC...AS WELL AS ACROSS
PORTIONS OF COSTA RICA AND NICARAGUA. THESE TWO ZONES WILL BE
THE FOCUS OF VERY HEAVY RAINFALL DURING THE NEXT 6 TO 12 HOURS
AND COULD LEAD TO LIFE THREATENING FLASH FLOODING WITH MUDSLIDES
POSSIBLE ACROSS STEEP TERRAIN.

GLOBAL MODELS CONTINUE TO SHOW THE POTENTIAL FOR TROPICAL
CYCLOGENESIS TO OCCUR WITHIN THE MONSOON TROUGH WITH DEVELOPING
LOW PRESSURE CENTERS SITUATED IN THESE TWO EXTREMELY WET ZONES.
A LOW CENTER OFFSHORE OF MANZANILLO IS FORECAST TO SHIFT SLOWLY
W-SW DURING THE NEXT FEW DAYS AND SLOWLY BECOME BETTER
ORGANIZED. MEANWHILE A SECOND LOW ALONG THE CARIBBEAN COASTAL
BORDER OF COSTA RICA AND NICARAGUA THIS MORNING IS EXPECTED TO
DRIFT W ACROSS THESE COUNTRIES OVER THE NEXT 24 TO 36 HOURS AND
PRODUCE VERY HEAVY RAINFALL. AS THIS SYSTEM EMERGES IN THE E
PACIFIC...GLOBAL MODELS ARE NEARLY UNANIMOUS IN SHOWING
POTENTIAL FOR DEVELOPMENT OF A TROPICAL CYCLONE DURING THE FIRST
PART OF THE UPCOMING WEEK AS THIS FEATURE MOVES WESTWARD.

ELSEWHERE AT THE SURFACE...NW FLOW WILL CONTINUE TO PULSE AT
15-20 KT ALONG THE W COAST OF THE BAJA CALIFORNIA PENINSULA...
AND 10-15 KT IN THE GULF OF CALIFORNIA. A NEW PULSE OF LONG
PERIOD SOUTHERLY SWELL IS CURRENTLY CROSSING THE EQUATOR AND
WILL EVENTUALLY MIX WITH THE SW SWELLS IN THE MONSOONAL FLOW
OVER THE WEEKEND.

$$
STRIPLING

000
ABNT20 KNHC 160435
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 AM EDT SAT JUL 16 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER BEVEN

000
AXPZ20 KNHC 160249
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT JUL 16 2011

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0215 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH IS ALONG 12N86W TO 1006 MB LOW PRES AT 15N95W
TO 17N102W...THEN RESUMES NEAR 15N112W TO 10N130W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 10N130W TO 07N140W.
SCATTERED MODERATE CONVECTION IS N OF 05N BETWEEN 82W AND 86W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS FROM 08N TO 13N
BETWEEN 92W AND 104W. SCATTERED MODERATE CONVECTION IS FROM 09N
TO 12N BETWEEN 118W AND 126W.

...DISCUSSION...
A LONGWAVE UPPER LEVEL TROUGH IS OVER THE WESTERN CONUS THAT
EXTENDS SOUTHWARD INTO DISCUSSION AREA WITH AXIS EXTENDING ALONG
32N124W TO 23N133W. AN EMBEDDED SHORTWAVE TROUGH IS NOTED ON
WATER VAPOR IMAGERY SW OF THE SOUTHERN CALIFORNIA COAST ALONG
123W. AN UPPER LEVEL ANTICYCLONE IS CENTERED JUST W OF THE AREA
AT 22N149W THAT CONTINUES TO DRIFT WESTWARD. THE UPPER LEVEL
RIDGING EXTENDS EASTWARD INTO THE AREA SOUTH OF THE PREVIOUSLY
MENTIONED TROUGH TO 18N123W. THE UPPER LEVELS REMAIN VERY DRY N
OF 15N W OF 115W.

A LONGWAVE UPPER LEVEL ANTICYCLONE IS OVER THE CENTRAL CONUS
THAT INCLUDES MOST OF NORTHERN MEXICO AND THE SOUTHERN BAJA
CALIFORNIA/GULF OF CALIFORNIA REGION. THE UPPER LEVEL RIDGE AXIS
EXTENDS SW INTO THE NE PACIFIC WATERS NEAR 18N115W. THIS STOUT
RIDGING IS RETARDING THE EASTWARD ADVANCE OF THE APPROACHING
UPPER TROUGHS. THE ASSOCIATED ANTICYCLONIC FLOW ALSO COVERS THE
TROPICS E OF 115W...BUT IS INTERRUPTED BY AN EMBEDDED UPPER
LEVEL CYCLONE NEAR 21N94W UPPER LEVEL DIFFLUENCE HAS BEEN
ENHANCING CONVECTION...ASSOCIATED WITH THE MONSOON TROUGH...
ALONG THE W COAST OF CENTRAL AMERICA. THE DEBRIS MOISTURE IS
ADVECTING SOUTHWESTWARD OVER THE ENTIRE AREA E OF 110W AND ALSO
MERGES WITH ADDITIONAL MIDDLE TO UPPER LEVEL MOISTURE ASSOCIATED
WITH THE WESTERN PORTION OF THE MONSOON TROUGH AND THE
ITCZ...ROUGHLY COVERING THE AREA FROM 05N TO 12N BETWEEN 110W
AND 138W.

THE LARGE ANTICYCLONE OVER THE CENTRAL CONUS IS EXPECTED TO
CONTINUE TO BLOCK THE UPPER TROUGH ALONG THE W COAST OF THE
CONUS THROUGH THE WEEKEND WITH THE UPPER LEVEL CYCLONE NEAR
21N94W EXPECTED TO CONTINUE WESTWARD EMBEDDED IN THE
ANTICYCLONIC FLOW...REACHING A POSITION OVER THE E PACIFIC NEAR
20N110W ON SUN. AN ASSOCIATED SURFACE LOW IS FORECAST NEAR
16N105W ON SUN WITH A LARGE AREA OF SOUTHWESTERLY MONSOONAL FLOW
CONTINUING TO THE SE OF THIS SURFACE LOW. THE 1007 MB SURFACE
LOW OVER NORTHERN COSTA RICA MAY ALSO MAINTAIN ITS CIRCULATION
AS IT DRIFTS WESTWARD INTO THE PACIFIC ALONG 10N THIS WEEKEND.

UPPER DIFFLUENCE...ABUNDANT UPPER MOISTURE...AND CONVERGENT
MONSOONAL LOW LEVEL FLOW WILL SUPPORT AREAS OF WIDESPREAD
RAINFALL WITH LOCALIZED TRAINING DEEP CONVECTION ACROSS CENTRAL
AMERICA DURING THE NEXT FEW DAYS. THIS MAY RESULT IN FLASH
FLOODS AND MUDSLIDES THROUGH THE WEEKEND.

ELSEWHERE AT THE SURFACE...NW FLOW WILL CONTINUE TO PULSE AT
15-20 KT ALONG THE W COAST OF THE BAJA CALIFORNIA PENINSULA...
AND 10-15 KT IN THE GULF OF CALIFORNIA. SOUTHWESTERLY WINDS AT
15-25 KT...SEAS TO 11 FT....WILL CONTINUE OVER THE TROPICAL
WATERS S OF 15N E OF 110W THROUGH THE WEEKEND. A NEW PULSE OF
SOUTHERLY SWELL IS EXPECTED TO CROSS THE EQUATOR LATE SATURDAY
EVENTUALLY MIXING WITH THE SW SWELLS IN THE MONSOONAL FLOW.

$$
HUFFMAN

000
ABNT20 KNHC 152315
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 PM EDT FRI JUL 15 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER BEVEN

000
AXPZ20 KNHC 152131
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI JUL 15 2011

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2115 UTC.

...ITCZ/MONSOON TROUGH...
THE MONSOON TROUGH IS ALONG 14N92W TO 1009 MB LOW PRES AT 15N95W
TO 17N103W...THEN RESUMES FROM 14N108W TO 09N128W. THE
INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 09N128W TO BEYOND
06N140W. SCATTERED MODERATE CONVECTION IS N OF 05N BETWEEN 80W
AND 88W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS N
OF 09N BETWEEN 92W AND 105W. SCATTERED MODERATE CONVECTION IS
FROM 08N TO 12N BETWEEN 105W AND 112W.

...DISCUSSION...
A LONGWAVE UPPER LEVEL TROUGH IS OVER THE WESTERN CONUS THAT
EXTENDS SOUTHWARD INTO DISCUSSION AREA WITH AXIS EXTENDING FROM
32N124W TO 26N132W. AN EMBEDDED SHORTWAVE TROUGH IS NOTED ON
WATER VAPOR IMAGERY SW OF THE SOUTHERN CALIFORNIA COAST ALONG
123W. AN UPPER LEVEL ANTICYCLONE IS CENTERED JUST W OF THE AREA
AT 21N146W THAT CONTINUES TO DRIFT WESTWARD. THE UPPER LEVEL
RIDGING EXTENDS EASTWARD INTO THE AREA SOUTH OF THE
AFOREMENTIONED TROUGH TO 17N125W. THE UPPER LEVELS REMAIN VERY
DRY N OF 16N W OF 115W.

A LONGWAVE UPPER LEVEL ANTICYCLONE IS OVER THE CENTRAL CONUS
THAT INCLUDES MOST OF NORTHERN MEXICO AND THE SOUTHERN BAJA
CALIFORNIA REGION. THE UPPER LEVEL RIDGE AXIS EXTENDS SW INTO
THE NE PACIFIC WATERS NEAR 20N118W. THIS STOUT RIDGING IS
RETARDING THE EASTWARD ADVANCE OF THE APPROACHING UPPER TROUGHS.
THE ASSOCIATED ANTICYCLONIC FLOW ALSO COVERS THE TROPICS E OF
115W...BUT IS INTERRUPTED BY EMBEDDED SMALL UPPER CYCLONES AT
21N93W AND 16N83W. UPPER LEVEL DIFFLUENCE HAS BEEN ENHANCING
CONVECTION...ASSOCIATED WITH THE MONSOON TROUGH...ALONG THE W
COAST OF CENTRAL AMERICA. THE DEBRIS MOISTURE IS ADVECTED
SOUTHWESTWARD OVER THE ENTIRE AREA E OF 110W AND ALSO MERGES
WITH ADDITIONAL MIDDLE TO UPPER LEVEL MOISTURE ASSOCIATED WITH
THE WESTERN PORTION OF THE MONSOON TROUGH AND THE ITCZ...ROUGHLY
COVERING THE AREA FROM 05N TO 12N BETWEEN 110W AND 138W.

THE LARGE ANTICYCLONE OVER THE CENTRAL CONUS IS EXPECTED TO
CONTINUE TO BLOCK THE UPPER TROUGH ALONG THE W COAST OF THE
CONUS THROUGH THE WEEKEND WITH THE UPPER LEVEL CYCLONE NEAR
21N93W EXPECTED TO CONTINUE WESTWARD EMBEDDED IN THE
ANTICYCLONIC FLOW...REACHING A POSITION OVER THE E PACIFIC NEAR
22N108W ON SUN. AN ASSOCIATED SURFACE LOW IS FORECAST NEAR
16N105W ON SUN WITH A LARGE AREA OF SOUTHWESTERLY MONSOONAL FLOW
CONTINUING TO THE SE OF THIS SURFACE LOW. THE 1008 MB SURFACE
LOW OVER NORTHERN COSTA RICA MAY ALSO MAINTAIN ITS CIRCULATION
AS IT DRIFTS WESTWARD INTO THE PACIFIC NEAR 10N86W THIS WEEKEND.

UPPER DIFFLUENCE...ABUNDANT UPPER MOISTURE...AND CONVERGENT
MONSOONAL LOW LEVEL FLOW WILL SUPPORT AREAS OF WIDESPREAD
RAINFALL WITH LOCALIZED TRAINING DEEP CONVECTION ACROSS CENTRAL
AMERICA DURING THE NEXT FEW DAYS. THIS MAY RESULT IN FLASH
FLOODS AND MUDSLIDES THROUGH THE WEEKEND.

ELSEWHERE AT THE SURFACE...NW FLOW WILL CONTINUE TO PULSE AT
15-20 KT ALONG THE W COAST OF THE BAJA CALIFORNIA PENINSULA...
AND 10-15 KT IN THE GULF OF CALIFORNIA. SOUTHWESTERLY WINDS AT
15-25 KT...SEAS TO 11 FT....WILL CONTINUE OVER THE TROPICAL
WATERS S OF 15N E OF 115W THROUGH THE WEEKEND. A NEW PULSE OF
SOUTHERLY SWELL IS EXPECTED TO CROSS THE EQUATOR LATE SATURDAY
EVENTUALLY MIXING WITH THE SW SWELLS IN THE MONSOONAL FLOW.

$$
HUFFMAN

000
ABNT20 KNHC 151747
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
200 PM EDT FRI JUL 15 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS.

$$
FORECASTER STEWART

000
AXPZ20 KNHC 151549
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI JUL 15 2011

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1545 UTC.

...ITCZ/MONSOON TROUGH...
BROAD LOW PRES OVER THE W CARIBBEAN IS ANALYZED AS A SURFACE LOW
AT 11N83W WITH THE MONSOON TROUGH EXTENDING NW OVER INTERIOR
CENTRAL AMERICA FROM THIS LOW PRES TO NEAR 14N89W...THEN THE
TROUGH CONTINUES ALONG THE PACIFIC COAST OF MEXICO TO NEAR
20N107W. THE MONSOON TROUGH RESUMES OVER THE PACIFIC NEAR
15N106W...AND CONTINUES SW TO 09N130W WHERE LOW LEVEL WINDS
INDICATE THE AXIS OF THE INTERTROPICAL CONVERGENCE ZONE
BEGINS...AND CONTINUES SW TO TO BEYOND 06N140W.

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90
NM EITHER SIDE OF A LINE FROM 07N82W TO 10N88W...AND N OF 10N TO
THE COAST OF MEXICO BETWEEN 93W AND 103W...AND ALSO WITHIN 150
NM EITHER SIDE OF A LINE FROM 10N107W TO 09N129W. SCATTERED
MODERATE CONVECTION IS OBSERVED FROM 03N TO 05N BETWEEN 79W AND
88W...AND WITHIN 15 NM LINE 07N129W TO 06N140W.

...DISCUSSION...
A LONG WAVE TROUGH OVER W COAST OF N AMERICA CONTINUES S INTO
THE DISCUSSION AREA WITH ITS MEAN AXIS EXTENDING FROM 32N126W TO
22N134W. AN EMBEDDED SHORTWAVE TROUGH IS NOTED FROM SOUTHERN
CALIFORNIA TO 23N116W. AN UPPER LEVEL ANTICYCLONE CENTERED JUST
W OF THE AREA AT 23N144W HAS AN UPPER RIDGE EXTENDING E INTO THE
AREA TO THE S OF THE UPPER TROUGH...TO A CREST AT 20N133W. THE
UPPER LEVELS ARE VERY DRY N OF 18N W OF 116W.

A LONG WAVE UPPER ANTICYCLONE IS OVER THE TEXAS AND OKLAHOMA
BORDER WITH AN UPPER RIDGE EXTENDING SW TO A CREST AT 21N114W...
AND IS RETARDING THE FORWARD ADVANCE OF THE APPROACHING UPPER
TROUGHS. THE ASSOCIATED ANTICYCLONIC FLOW ALSO COVERS THE
TROPICS E OF 110W...BUT IS INTERRUPTED BY EMBEDDED SMALL UPPER
CYCLONES AT 21N92W AND 13N82W. UPPER LEVEL DIFFLUENCE HAS BEEN
ENHANCING CONVECTION...ASSOCIATED WITH THE PREVIOUSLY DESCRIBED
MONSOON TROUGH...ALONG THE W COAST OF CENTRAL AMERICA. THE
DEBRIS MOISTURE IS ADVECTED SW OVER THE ENTIRE AREA E OF 110W
AND ALSO MERGES WITH ADDITIONAL DEBRIS MOISTURE ASSOCIATED WITH
THE WESTERN SEGMENT OF THE MONSOON TROUGH AND THE ITCZ...ROUGHLY
COVERING THE UPPER LEVELS FROM 05N TO 12N BETWEEN 110W AND
137W.

THE LARGE ANTICYCLONE OVER THE CENTRAL CONUS IS EXPECTED TO
CONTINUE TO BLOCK THE UPPER TROUGH TO ALONG THE W COAST OF THE
CONUS. THE UPPER CYCLONE NEAR 21N92W IS EXPECTED TO CONTINUE
WESTWARD EMBEDDED IN THE ANTICYCLONIC FLOW...REACHING A
POSITION OVER THE E PACIFIC NEAR 20N104W ON SUN. AN ASSOCIATED
SURFACE LOW IS FORECAST NEAR 16N104W ON SUN WITH SOUTHWESTERLY
MONSOONAL FLOW CONTINUING TO THE SE OF THIS SURFACE LOW. THE
SURFACE LOW OVER THE W CARIBBEAN MAY ALSO MAINTAIN ITS
CIRCULATION AS IT DRIFTS W ACROSS COSTA RICA INTO THE PACIFIC
NEAR 10N86W LATE THIS WEEKEND.

UPPER DIFFLUENCE...ABUNDANT UPPER MOISTURE...AND CONVERGENT
MONSOONAL LOW LEVEL FLOW WILL SUPPORT AREAS WIDESPREAD RAINFALL
WITH LOCALIZED TRAINING DEEP CONVECTION ACROSS CENTRAL AMERICA
DURING THE NEXT FEW DAYS. THIS MAY RESULT IN FLASH FLOODS AND
MUDSLIDES THROUGH THE WEEKEND. A GRAPHICAL REPRESENTATION IS
PRESENTED AT ://WWW.HURRICANES.GOV/MARINE.

ELSEWHERE AT THE SURFACE...NW FLOW WILL CONTINUE TO PULSE AT
15-20 KT ALONG THE W COAST OF BAJA CALIFORNIA PENINSULA...AND
10-15 KT IN THE GULF OF CALIFORNIA. SOUTHWESTERLY WINDS AT 15-25
KT...SEAS TO 11 FT....WILL CONTINUE OVER THE TROPICAL WATERS S
OF 15N E OF 115W THROUGH THE WEEKEND. A NEW PULSE OF SOUTHERLY
SWELL IS EXPECTED TO CROSS THE EQUATOR SAT NIGHT EVENTUALLY
MIXING WITH THE SW SWELLS IN THE MONSOONAL FLOW.

$$
NELSON

000
ABNT20 KNHC 151139
TWOAT

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT FRI JUL 15 2011

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

AN AREA OF DISTURBED WEATHER IS MOVING INLAND OVER NICARAGUA AND
COSTA RICA...AND INTERACTION WITH LAND IS EXPECTED TO PREVENT
DEVELOPMENT OF THIS DISTURBANCE. THIS SYSTEM HAS A LOW CHANCE
...NEAR 0 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT
48 HOURS. HOWEVER...LOCALLY HEAVY RAINFALL WILL BE POSSIBLE OVER
PORTIONS OF CENTRAL AMERICA DURING THE NEXT FEW DAYS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER STEWART

000
AXPZ20 KNHC 150957
TWDEP

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JUL 15 2011

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
0915 UTC.

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH AXIS MEANDERS ACROSS CENTRAL AMERICA FROM
DEVELOPING LOW PRES ALONG THE NICARAGUA-COSTA RICA BORDER NW TO
NEAR 19N102W. A SECOND SEGMENT OF MONSOON TROUGH EXTENDED FROM
BROAD CYCLONIC TURNING NEAR 17N11W TO 15N119W TO 09N129W WHERE
IT THEN BECOME ITCZ...EXTENDING THROUGH 06N140W. SCATTERED
MODERATE ISOLATES STRONG CONVECTION WAS WITHIN 90 NM OF ITCZ
AXIS. SCATTERED MODERATE TO STRONG CONVECTION WAS FROM 03N
BETWEEN 80W AND 89W TO THE COAST OF COSTA RICA AND NICARAGUA.
SCATTERED TO LOCALLY NUMEROUS STRONG CONVECTION WAS WITHIN 210
NM OF MEXICAN COAST BETWEEN 93W AND 106W. SCATTERED MODERATE
ISOLATED STRONG CONVECTION WAS ELSEWHERE FROM 07N TO 12N BETWEEN
97W AND 124W.

...DISCUSSION...
AT UPPER LEVELS...A STRONG BLOCKING RIDGE ACROSS CENTRAL N
AMERICA ALONG ABOUT 96-97W WAS CENTERED ON AN ANTICYCLONE OVER
OKLAHOMA...WITH THIS RIDGE FORECAST TO REMAIN IN PLACE FOR THE
NEXT FEW DAYS BEFORE BEGINNING TO SHIFT SLOWLY NE DURING THE
MIDDLE OF NEXT WEEK. THIS RIDGE HAS HALTED TO FORWARD PROGRESS
OF A LONG WAVE UPPER TROUGH EXTENDING FROM WRN CANADA SW TO A
WEAKENING MIDDLE TO UPPER VORTEX NEAR 34N128W THEN CONTINUES TO
NEAR 26N135W. BROAD CYCLONIC FLOW ALOFT COVERS THE AREA N OF 24N
W OF 115W. S OF THIS BROAD CYCLONIC FLOW...AN UPPER ANTICYCLONE
WAS CENTERED NEAR 20N137W AND SHIFTING GRADUALLY SW. MIDDLE TO
UPPER CONVERGENCE WAS YIELDING A VERY STABLE ATMOSPHERE
GENERALLY N OF 18N AND W OF 115W. TO THE S AND SE OF THESE
FEATURES...WINDS ALOFT WERE NE TO ELY AND WERE PROVIDING A
MODESTLY SHEARED ENVIRONMENT ALOFT CONDUCIVE FOR THE DEEP
CONVECTION DESCRIBED ABOVE.

AT LOW TO MIDDLE LEVELS...THE GFS MODEL DEPICTS DEEP LAYERED
MONSOONAL FLOW ELONGATED NW TO SE FROM COASTAL MEXICO NEAR
MANZANILLO TO COSTA RICA AND WRN PANAMA AND THE ADJACENT SW
CARIBBEAN AND PACIFIC WATERS. ABUNDANT TROPICAL MOISTURE
CONTINUES TO CONVERGE ACROSS THIS REGION FROM 110W TO THE FAR SW
CARIBBEAN. SATELLITE IMAGERY THE PAST 6 HOURS OR SO CONFIRM
GLOBAL MODEL FORECASTS INDICATING TWO CENTRAL CYCLONIC
CIRCULATIONS DEVELOPING EACH END OF THE MONSOON TROUGH...ONE
ACROSS SW MEXICO...AND THE OTHER STRADDLING WRN PANAMA...COSTA
RICA...AND NICARAGUA. RECENT SCATTEROMETER PASSES SUGGEST SW TO
WLY WINDS ACROSS THE NEAR AND OFFSHORE PACIFIC WATERS OF COSTA
RICA ASSOCIATED WITH A DEVELOPING LOW...WHILE WLY WINDS AROUND
20 KT WERE SUGGESTED FROM 07N TO 14N BETWEEN 96W AND 103W. THESE
ZONES OF FRESH MONSOONAL FLOW WERE AIDING IN THE INITIATION OF
THE ABOVE DESCRIBED CONVECTION.

GLOBAL MODELS ARE SLOWLY COMING INTO BETTER AGREEMENT ON THE
EVOLUTION OF THE MONSOONAL TROUGH AND ASSOCIATED LOWS OVER THE
NEXT FEW DAYS. THIS TROUGH IS EXPECTED TO BECOME SOMEWHAT MORE W
TO E ALIGNED OVER THE NEXT FEW DAYS AND ALLOW A BROAD SURFACE
LOW TO DEVELOP OFF THE SW MEXICAN COAST LATE SAT...WITH SOME
POTENTIAL FOR INTENSIFICATION SUN THROUGH MON AS IT MOVES W OVER
WARM WATERS. MEANWHILE...LOW PRES STRADDLING COSTA RICA IS
SUGGESTED TO CONTINUE TO INTERACT WITH THESE CENTRAL AMERICAN
LAND MASSES AND EVENTUALLY FULLY EMERGE OFF THE NW COAST OF
COSTA RICA AND SW NICARAGUA LATE SUN OR MONDAY...AND COULD ALSO
INTENSIFY AS IT MOVES W OVER WARM WATERS. THE GFS MODEL
CONTINUES TO BE VERY AGGRESSIVE IN DEVELOPING THE LOW OFF OF
COSTA RICA...AND DEEPENS IT VERY QUICKLY SUN-MON.
HOWEVER...THESE MONSOONAL TYPE LOWS ARE TYPICALLY SLOW TO
DEVELOP...AND HAVE TRENDED WITH SLOWER DEVELOPMENT INDICATED BY
THE OTHER GLOBAL MODELS. REGARDLESS OF THE SHORT TERM EVOLUTION
OF THESE LOWS...FRESH TO STRONG SW TO W MONSOONAL FLOW WILL
CONTINUE FOR THE NEXT 36-48 HOURS ACROSS MUCH OF THE TROPICAL
EPAC E OF 90W AND ACROSS THE OFFSHORE MEXICAN WATERS BETWEEN
ACAPULCO AND THE GULF OF TEHUANTEPEC. ABUNDANT TROPICAL MOISTURE
AND PERSISTENT DEEP CONVECTION ACROSS CENTRAL AMERICA DURING THE
NEXT FEW DAYS WILL CONTINUE TO PRODUCE WIDESPREAD RAINFALL AND
PERIODS OF VERY HEAVY RAINS RESULTING IN FLASH FLOODS AND
MUDSLIDES THROUGH THE WEEKEND. LONGER DURATION RIVER FLOODING
MAY ALSO BE SEEN INTO EARLY NEXT WEEK. ADDITIONAL INFORMATION IS
CONTAINED IN TAFB GRAPHICASTS AT
://WWW.HURRICANES.GOV/MARINE.

W OF 110W...SCATTEROMETER AND SHIP DATA SHOW FRESH NW FLOW ALONG
THE COAST OF BAJA PERSISTING BETWEEN 1037 MB HIGH PRES NEAR
42N154W...AND TROUGHING OVER THE GULF OF CALIFORNIA...AND THIS
SHOULD PERSIST THROUGH 48 HOURS WITH NW WINDS TO 20 KT
DEVELOPING THROUGH THE CENTRAL GULF OF CALIFORNIA WITHIN 24
HOURS. FURTHER SOUTH...TRADE WINDS REMAIN ANOMALOUSLY LIGHT.
REGIONAL SEAS ARE CURRENTLY DOMINATED BY FADING LONG PERIOD SW
SWELL...WITH A NEW PULSE OF S SWELL EXPECTED TO CROSS THE
EQUATOR LATE SAT.

$$
STRIPLING