Tropical Weather Discussion

axpz20 knhc 172215

Tropical weather discussion
NWS National Hurricane Center Miami FL
2205 UTC sun Feb 17 2019

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 
2000 UTC.

...Intertropical convergence zone/monsoon trough...updated 

A surface trough extends from northwestern Colombia to to 06n78w 
to 08n87w to 07n91w. The ITCZ begins from 06.5n93w to 02n109w to 
00n128w. Isolated clusters of moderate convection are noted 
within 120 nm of the ITCZ between 89w and 109w.


Offshore waters within 250 nm of Mexico...  

A strong and persistent ridge extends southeastward across the 
discussion area, through 32n137w to near 10n107w. The tight 
pressure gradient between the ridge and lower surface pressure 
that is present over the southwestern United States and Mexico 
has been supporting strong northwest winds across the offshore 
waters for over 24 hours, and have finally begun to diminish to 
around 18-25 kt this afternoon as the ridge is realigning. Seas 
associated with these winds are in 9-14 ft range in NNW swell, 
and marine conditions remain rough and dangerous. 

A new cold front is sinking SSE across the offshore waters of 
Southern California this afternoon and will sweep across far 
north portions of Baja California tonight through Tue morning 
and reinforce this NW wind flow. However, this will also weaken 
slightly the pressure gradient and lead to winds continuing to 
slowly diminish to 15-20 kt across most of the waters by Mon 
night, then becoming moderate to fresh Tue and Wed. Seas will 
also gradually subside tonight through Mon as the current large 
NW swell moves se of the area. However, reinforcing NNW swell 
from this next approaching cold front will maintain seas at 7-11 
ft Tue through Wed.

Gulf of california: low pressure and its associated cold front 
will move across the northern part of the Gulf of California 
tonight, bringing fresh to strong SW to W winds to the northern 
part of the Gulf of California ahead of the front tonight, and 
then fresh to strong NW winds behind the front midday Mon 
through Mon night. Fresh northerly wind flow is then expected 
throughout most of the Gulf on Tue and diminishing to moderate 
to locally fresh Tue night through Wed.

Offshore waters within 250 nm of Central America, Colombia, and 
within 750 nm of Ecuador...

Gentle northeast winds across the Gulf of papagayo will increase
again to the mainly moderate speeds on Mon, and to stronger
speeds of fresh to moderate Mon night into Tue. Light and 
variable winds are expected elsewhere through Tue, except for 
the Gulf of Panama where moderate northerly winds are expected.

Remainder of the area... 

A very strong 1041 mb high pressure center, well to the north- 
northeast of the Hawaiian islands near 41n144w, will change 
little through Tue. The associated ridge axis stretches 
southeastward to tropics to near 10n107w, which has forced the 
ITCZ southward to near the Equator. The pressure difference 
between this ridge and broad low pressure lingering across the 
Hawaiian islands area is resulting in a tight pressure gradient 
across the area N of about 08n and W of 110w. Northeast to east 
winds of 20 to 25 kt are generally west of a line from 30n140w 
to 12.5n127w to 10n140w, where seas are in the range of 10 to 15 
ft. This current overall synoptic pattern will change very 
little through the next couple of days as low pressure west of 
the area near 24n155w pulls off to the northwest. The area of 
strong northeast to east winds will continue, but over a 
gradually smaller section of the western side of the discussion 
area. The seas there will slowly subside to around the 10 to 12 
ft through the next 48 hours as the large swell gradually 
propagates se of the area.



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