Post
by DoctorMu » Sun Sep 17, 2023 2:34 pm
Right here, right now - low to mid 90s through the week a 20% chance of rain in the latter half. The previously progged zonal flow (that was POW) is now expected by NWS to become amplified and a weak battle of ridging vs. NW flow disturbances/shortwaves is expected to complicate the forecast after Tuesday.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
230 PM CDT Sun Sep 17 2023
...New SHORT TERM, LONG TERM, MARINE...
.SHORT TERM...
(This evening through Monday Night)
Issued at 230 PM CDT Sun Sep 17 2023
Drier air filtering in from the north combined with ridging building
aloft means that the weather today is being much quieter compared
the past few days. The dry air and mid-level ridging will remain in
place through tomorrow, so expect a very similar conditions for the
start of the work week. Surface winds do begin to become
southeasterly by Monday night increasing low level moisture of the
region. But at most, this moisture looks to bring just some isolated
showers over the coastal waters during the overnight period.
Temperatures through the short term will be near to slightly above
normal. Overnight temperatures tonight and Monday night will be in
the upper 60s to low 70s for most of the area (near shore areas will
be in the upper 70s to near 80 degrees). High temperatures on Monday
will be a couple of degrees warmer than today with afternoon
temperatures rising into the low to mid 90s.
Fowler
&&
.LONG TERM...
(Tuesday through next Saturday)
Issued at 230 PM CDT Sun Sep 17 2023
Onshore flow and ridging aloft will be firmly in place by Tuesday,
but moisture around the area doesn`t really increase all that
much...at least not initially. PW values remain generally below
1.4", which is fairly close to the 25th percentile (~1.20"). So,
even with northwesterly flow aloft prevailing, there may not be
enough moisture for any passing shortwave disturbances to generate
much more than isolated to scattered showers/storms. The best
chance for rain this week looks to be late Tuesday into Wednesday
when an embedded shortwave trough sneaks through the flow aloft,
but this also may be hindered by upper level jet dynamics. Going
into Tuesday afternoon, an anticyclonically curved jet streak
moves in over Southeast Texas. We`ll mainly be beneath the right
exit region which is an area of upper level convergence or NVA. In
layman`s terms, that`s an unfavorable ingredient if you want to
generate the lift needed for convection. That being said, PoPs
have been limited to generally in the 30% range.
Towards the end of the week, the ridge is still expected to become
amplified as an upper level low dips down into the western CONUS.
500mb heights increase to 590-592 dam for Thursday and parts of
Friday. This along with PW values remaining climatologically dry has
lead to a warmer trend in temperatures at the end of the week. High
temperatures will go from the low to mid 90s on Tuesday/Wednesday to
the mid to upper 90s by Thursday. Additionally, PW values begin to
increase to near 1.7"-1.8" by Thursday/Friday as well (75th
percentile: ~1.82"), so showers/storms along the seabreeze will be a
possibility. Another upper level low develops over Florida some time
on Friday and creates a synoptic pattern that is somewhat reminiscent
of an omega block pattern...but tilted. This isn`t a true blocking
pattern though and features aloft will continue to move. However,
the northward progression of the upper level low over Florida will
play a factor in how far south the western CONUS upper level low
tracks...and as of right now it doesn`t look too favorable for it to
come far south enough to drag its associated cold front through
Southeast Texas. We should be in the warm sector of the coinciding
surface low though as it drifts through the Northern Plains, so warm
and humid conditions are expected to persist into next weekend.
Batiste