356
axpz20 knhc 211000
twdep
Tropical weather discussion
NWS National Hurricane Center Miami FL
1005 UTC Mon may 21 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 0600 UTC surface analysis and satellite imagery through
0900 UTC.
...Special feature...
Tropical Depression Two-E remains embedded in monsoon trough...
but maintains good outflow aloft. Warm SST...plenty of
available moisture and low shear keeps system ready for slow
intensification. Clusters of moderate to strong deep convection
noted in bands around southern semicircle and NW quadrant of
center. See latest tropical cyclone advisory wtpz22/tcmep2 knhc
for further details on Tropical Depression Two-E.
...Intertropical convergence zone/monsoon trough...
monsoon trough extends from 10n86w to 12n94w to Tropical
Depression Two-E at 09.3n99.9w to 06n121w then ITCZ to 06n129w
to beyond 03n140w. Isolated moderate convection within 90 nm of
trough axis E of 98w.
...Discussion...
upper level trough cuts through NW corner of basin from 32n128w
to deep layer cyclone at 19n141w then turn se to 00n119w. Very
dry subsiding air mass cover extensive part of E pac N of 16n
and also W of 116w. Well defined anticyclone at 18n107w is
unable to advect any significant tropical moisture from ITCZ/
monsoon trough northward. Elsewhere...weak ridge along 09n/10n
provides favorable divergent flow aloft for low pres at 09.3n
99.3w to enhance scattered deep convection within 300 nm se and
360 nm SW of center of depression two-E. Model guidance
strengthen system and steer it NW then turning N within 48 hours
posing a threat to Mainland Mexico. Interests should monitor
details of Tropical Depression Two-E at the above mentioned NHC
products.
..at the lower levels...
Divergent flow aloft and light anticyclonic wind shear S of the
ridge is maintaining a very favorable environment for deep
convection. Abundant tropical moisture is pooled S of the
monsoon trough E of 105w. Scattered moderate to strong
convection continues to pulse in clusters across this very
unstable region...further enhancing divergence aloft...and
aiding in the maintenance of the upper level ridge.
Fresh to strong N-NE winds continue over Gulf of Tehuantepec due
to pres gradient between ridge in western Gulf of Mexico and
trough over E coast of Yucatan Peninsula. Winds expected to
extend to the N of Tropical Depression Two-E enhancing low level
wind convergence.
High pres just NW of basin extend weak ridge to 15n115w keeping
stratified low level clouds devoid of vertical development.
Associated pres gradient support moderate to fresh NE trades
within next 24-36 hrs winds.
Remnant low of Tropical Depression Aletta now a weak trough
barely identified in 0600 UTC analysis.
$$
Wally Barnes
