Tropical Weather Discussion

axpz20 knhc 271009

Tropical weather discussion 
NWS National Hurricane Center Miami FL
1005 UTC Fri Nov 27 2015

Tropical weather discussion for the eastern Pacific Ocean from  
the Equator to 32n...east of 140w. The following information is 
based on satellite observations...radar...and 
meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
0945 UTC.               

...Special features...

At 0900 UTC...Hurricane Sandra was centered near 18.9n 109.3w
...Or about 243 nm S of the southern tip of the Baja California
peninsula. Sandra is moving N-NE at 10 kt. The estimated minimum
central pressure was 969 mb. Maximum sustained winds are 90 kt
with gusts to 110 kt. Numerous moderate to isolated strong
convection is from 18n to 21n between 105w and 109w. Scattered
moderate convection is elsewhere from 16n to 23n E of 110w. As
Sandra continues N-NE today...the upper level wind shear is
expected to increase across the system...and a fairly quick
weakening trend is expected...with Sandra reaching tropical
storm strength on Friday night as it approaches the southern tip
of Baja California. Interests in the southern portions of the
Baja Peninsula as well along the central Pacific coast of Mexico
should monitor the progress of Sandra. Occasional bands and
clusters of thunderstorms will affect the W coastal states of
Mexico from michoacan to sinaloa during the next 48 hours and
could produce large rainfall accumulations that may cause life
threatening flash floods and landslides. Large swells are in the
Pacific coast of Mainland Mexico...spreading north to the
southern portion of the Baja Peninsula today. See the latest NHC
forecast/advisory under AWIPS/WMO headers miatcmep2/wtpz22 knhc
for more details.

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

The monsoon trough axis extends from 06n77w to 07n89w...where it
is fractured...then resumes near 16n111w to 08n118w...where it
transitions to ITCZ...continuing on to beyond 04n140w. Scattered
moderate convection is from 02n to 07n E of 86w. 


Strong pressure gradient is supporting a band of strong NE 20-25
kt winds from 16n to 23n between 123w and 136w with combined
seas of 8-11 ft in mixed NW and NE swell. Elsewhere this long
period NW swell is mixing with NE wind waves and se swell from
Sandra...resulting in combined seas 8-10 ft to the N of line
from 16n118w to 19n121w to 18n130w to 19n140w. The pressure
gradient will increase with an area of NE 20-25 kt across the
tropical waters from 15n to 22n W of 126w on Sat...with 8-13 ft
seas prevailing. By sun the area of enhanced NE trades will
shift W to within the area from 13-18n W of 133w.

Gap winds...Gulf of Tehuantepec...the northerly wind flow across
and downstream of the Gulf prevails at 20-25 kt with maximum
seas to 8 ft. Expect N-NE surges of 20-30 kt across the Gulf
waters to as far S as 13n96w the next two days. Minimal gale
force conditions potentially developing on Sun night into Mon. 

Gulf of papagayo...a tight pressure gradient across the W and SW
Caribbean will continue to support pulses of NE to E 20-25 kt
winds today across the papagayo region and downstream to around
88w...with seas building to 9 ft. Computer model guidance
suggests a slightly stronger event on Sat night.



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Storm Coverage

Dr. Jeff Masters' Blog
By Dr. Jeff Masters, 11:18 AM EST on November 26, 2015
Director of Meteorology, Weather Underground
Remarkable Hurricane Sandra exploded into a Category 4 storm with 145 mph winds overnight, making it the latest major hurricane ever observed in the Western Hemisphere (November 26.) The previous record was held by an un [...]