000
AXPZ20 KNHC 012112
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN JUL 01 2012

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 1900 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0100 UTC.

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

THE MONSOON TROUGH AXIS IS INLAND OVER PANAMA...COSTA RICA...AND 
WESTERN NICARAGUA. THE ITCZ AXIS EXTENDS FROM 10N112W TO 11N117W 
TO 05N135W TO 05N140W. ISOLATED MODERATE CONVECTION IS WITHIN 
270 NM S AND 180 NM N OF THE AXIS BETWEEN 115W AND 126W AND 
ELSEWHERE WITHIN 90 NM N OF THE AXIS BETWEEN 112W AND 134W. A 
TROUGH JUST E OF THE ITCZ LIES ALONG 108W FROM 08N TO 12N. 
SCATTERED MODERATE CONVECTION CAN BE FOUND WITHIN 180 NM E OF 
THE TROUGH FROM 09N TO 12N AND S OF THE TROUGH FROM 05N TO 08N 
BETWEEN 103W AND 108W.

...TROPICAL WAVE...

A TROPICAL WAVE LIES ALONG 98W FROM 08N TO 14N. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 450 NM E OF 
THE WAVE FROM 09N TO 14N AND SCATTERED MODERATE CONVECTION IS S 
OF THE WAVE FROM 04N TO 07N BETWEEN 92W AND 103W. THIS WAVE LIES 
ON THE WEST EDGE OF A DEEP LAYER INVERTED TROUGH THAT IS 
SUPPORTING AN UPPER LOW EVIDENT IN WATER VAPOR IMAGERY OVER FAR 
SOUTHERN MEXICO. SOME OF THE FORECAST MODELS ARE SHOWING 
CONSOLIDATION OF THE MID LEVEL ENERGY ASSOCIATED WITH THE 
TROPICAL WAVE AND THE INVERTED TROUGH OVER THE NEXT FEW DAYS AND 
ALLOW THE DEVELOPMENT OF A SURFACE LOW ALONG THE WAVE. 
HOWEVER...SHEAR SHOULD DETER ANY SIGNIFICANT DEEPENING OF THIS 
LOW. 

...DISCUSSION...

SUBTROPICAL RIDGING REMAINS WEAK OVER THE FORECAST AREA. IT 
STEMS FROM 1030 MB HIGH PRES SYSTEM NEAR 38N156W. THE RIDGING 
OVER THE WESTERN PORTION OF THE FORECAST AREA REMAINS 
COMPROMISED BY AN UPPER TROUGH THAT EXTENDS FROM THE PACIFIC NW 
U.S. INTO NW FORECAST WATERS. TRADE WINDS ARE DOWN TO A MODERATE 
BREEZE AT THE MOMENT AND WILL HOVER NEAR 20 KT OVER FAR W WATERS 
JUST N OF THE ITCZ THROUGH TUE AFTERNOON. THE DEEP LAYER 
TROUGHING MOVING INTO THE WESTERN U.S. IS DECREASING SURFACE 
PRESSURES THERE AS HIGH PRES BUILDS BEHIND THE FRONT. THIS HAS 
RESULTED IN A TIGHT PRES GRADIENT THAT EXTENDS SOUTHWARD TO OFF 
BAJA CALIFORNIA. FRESH TO STRONG NW WINDS CAN BE FOUND AS FAR S 
AS 26N AND W OF THE PENINSULA TO 119W. ON MON...THE EASTERN EDGE 
OF THE RIDGE AXIS WILL DIP SOUTHWARD AND WINDS AND SEAS WILL 
BEGIN DIMINISHING OFF THE W COAST OF BAJA CALIFORNIA JUST AS 
SOUTHERLY FLOW INCREASES OVER THE GULF OF CALIFORNIA. 

DEEP LAYERED TROUGHING BETWEEN 105W AND 110W IS FORCING A 
SURFACE TROUGH N OF THE ITCZ ALONG 108W. CONVECTION FOUND 
PRIMARILY S AND E OF THE TROUGH IS DESCRIBED IN THE ITCZ/MONSOON 
TROUGH SECTION ABOVE. THIS TROUGH IS EXPECTED TO WEAKEN OVER THE 
NEXT TWO DAYS. 

GAP WINDS...
GULF OF PAPAGAYO...THE 1550 UTC ASCAT PASS CAPTURED FRESH 
EASTERLY FLOW DOWNWIND OF THE GULF OF PAPAGAYO TO 89W. THE 
GRADIENT BETWEEN HIGH PRES IN THE GULF OF MEXICO AND LOWER PRES 
TO THE SW WILL REMAIN STRONG ENOUGH THROUGH TUE FOR A SUSTAINED 
FRESH BREEZE IN THE GULF OF PAPAGAYO THAT IS EXPECTED TO BE 
STRONGER IN THE EARLY MORNING HOURS WITH THE ASSISTANCE OF 
DRAINAGE FLOW OFF THE LAND. 

GULF OF CALIFORNIA...FRESH SOUTHERLY WINDS ARE FORECAST TO BEGIN 
OVER THE GULF OF CALIFORNIA N OF 27N MON MORNING AS THE 
SUBTROPICAL RIDGE SINKS SOUTHWARD TOWARD NE WATERS. THESE WINDS 
WILL CONTINUE THROUGH THE END OF THE FORECAST PERIOD TUE 
AFTERNOON.
 
$$
SCHAUER