Re: January 2021
Posted: Mon Jan 18, 2021 9:13 am
00
FXUS64 KHGX 181033
AFDHGX
Area Forecast Discussion
National Weather Service Houston/Galveston TX
433 AM CST Mon Jan 18 2021
.SHORT TERM [Today through Tuesday Night]...
As the surface high pressure leaves our region, southeast winds will
return, bringing in some WAA and higher PWATs over SE Texas. That
being said, daytime highs will reach 70 for most of our CWA and
upper 60s everywhere else today and then reach the low-to-mid 70s on
Tuesday. Say goodbye to freezing temps as overnight lows tonight
will reach the upper 50s. Increased low-to-mid level moisture and an
approaching cold front will also bring in gradual cloud coverage
today.
On Tuesday, a positively tilted trough will be located over SW CONUS
and nearly zonal flow will be on top of our CWA. A surface cold
front is expected to push through SE Texas and stall across our
northwestern counties bringing the highest rain chances over those
areas. Despite daytime heating, warm theta-e advection, higher
PWATs, and surface convergence along the front, heavy rain is not
expected on Tuesday. This is due to residual dry air in the lower
and mid-levels along with a surface inversion due left over by the
previous high pressure system. However, the previous
aforementioned low-level forcing/moistening mechanisms will slowly
erode that inversion and enrich the low-to-mid levels. KBL &&
LONG TERM [Wednesday through Monday]...
Wednesday, rain chances continue to increase with the higher chances
west of I-45. The weak cold front, now quasi-stationary in the
northwestern/western region of the CWA. Higher rain chances will
still stay northward, mainly north of I-10 over Wednesday night.
While onshore flow continually brings gulf moisture into the area,
lack of instability will keep thunderstorm development minimal at
best. Thursday the system will start to drag across the CWA,
mostly parallel to the coastline, which may decrease rain chances
across the forecast area as lift weakens.
Friday the lift along the boundary will continue to move out the
area with some chances of rain still lingering in the northeastern
counties, but almost diminishes by Friday night. Friday night,
winds will begin shifting northeasterly as the front pushes to the
coastal waters into Saturday morning. Saturday will continue the
decrease in rain trend as onshore flow returns in the evening.
Sunday, onshore flow continues and rain chances return to SETX in
the wake of a warm front. Monday, a cold front approaches and is
expected to enter the northwestern counties in the morning and
pass through the southeastern counties Monday evening. 35
&&
.AVIATION [12Z TAF Issuance]...
VFR conditions expected this morning and afternoon. Gradually,
increasing cloud coverage will form at approximately 3000-5000 ft
this afternoon due to an approaching front and a VFR ceiling will
form near 19Z. Later tonight, that will transition to an MVFR
ceiling with OVC conditions at 2500 ft. This afternoon, SE winds
will gradually increase and become gusty. VCSH and possible SHRA
will begin towards the end of the TAF period for our northern
terminals such as CLL and UTS as that front approaches. KBL
&&
.MARINE...
Light winds this morning will become southeasterly and southerly
and begin strengthening as pressures lower of W TX this afternoon.
Southerly flow of 10 to 15 knots occasionally 15 to 20 knots will
persist through Tuesday (the stronger winds should be out beyond
20nm). Wednesday the flow backs to the east and southeast and this
should in turn increase the chances for sea fog over the colder
shelf waters. Thursday the low levels slowly moisten further as
winds come back to the south and the intermittent sea fog threat
will likely persist into the weekend. Some differences in the
extended guidance stand out going into Saturday afternoon/night
with either full southeasterly flow or the frontal boundary
stalling near the coast then very slowly lifting north.
Confidence in timing beyond Friday diminishes quickly but overall
expect a warming trend with increasing southerly flow Sunday
possibly approaching SCA.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 69 57 68 50 61 / 0 50 70 60 40
Houston (IAH) 69 58 72 54 67 / 0 20 30 30 30
Galveston (GLS) 64 60 67 57 63 / 0 10 10 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM/AVIATION...KBL
LONG TERM/MARINE/FIRE...35/45
FXUS64 KHGX 181033
AFDHGX
Area Forecast Discussion
National Weather Service Houston/Galveston TX
433 AM CST Mon Jan 18 2021
.SHORT TERM [Today through Tuesday Night]...
As the surface high pressure leaves our region, southeast winds will
return, bringing in some WAA and higher PWATs over SE Texas. That
being said, daytime highs will reach 70 for most of our CWA and
upper 60s everywhere else today and then reach the low-to-mid 70s on
Tuesday. Say goodbye to freezing temps as overnight lows tonight
will reach the upper 50s. Increased low-to-mid level moisture and an
approaching cold front will also bring in gradual cloud coverage
today.
On Tuesday, a positively tilted trough will be located over SW CONUS
and nearly zonal flow will be on top of our CWA. A surface cold
front is expected to push through SE Texas and stall across our
northwestern counties bringing the highest rain chances over those
areas. Despite daytime heating, warm theta-e advection, higher
PWATs, and surface convergence along the front, heavy rain is not
expected on Tuesday. This is due to residual dry air in the lower
and mid-levels along with a surface inversion due left over by the
previous high pressure system. However, the previous
aforementioned low-level forcing/moistening mechanisms will slowly
erode that inversion and enrich the low-to-mid levels. KBL &&
LONG TERM [Wednesday through Monday]...
Wednesday, rain chances continue to increase with the higher chances
west of I-45. The weak cold front, now quasi-stationary in the
northwestern/western region of the CWA. Higher rain chances will
still stay northward, mainly north of I-10 over Wednesday night.
While onshore flow continually brings gulf moisture into the area,
lack of instability will keep thunderstorm development minimal at
best. Thursday the system will start to drag across the CWA,
mostly parallel to the coastline, which may decrease rain chances
across the forecast area as lift weakens.
Friday the lift along the boundary will continue to move out the
area with some chances of rain still lingering in the northeastern
counties, but almost diminishes by Friday night. Friday night,
winds will begin shifting northeasterly as the front pushes to the
coastal waters into Saturday morning. Saturday will continue the
decrease in rain trend as onshore flow returns in the evening.
Sunday, onshore flow continues and rain chances return to SETX in
the wake of a warm front. Monday, a cold front approaches and is
expected to enter the northwestern counties in the morning and
pass through the southeastern counties Monday evening. 35
&&
.AVIATION [12Z TAF Issuance]...
VFR conditions expected this morning and afternoon. Gradually,
increasing cloud coverage will form at approximately 3000-5000 ft
this afternoon due to an approaching front and a VFR ceiling will
form near 19Z. Later tonight, that will transition to an MVFR
ceiling with OVC conditions at 2500 ft. This afternoon, SE winds
will gradually increase and become gusty. VCSH and possible SHRA
will begin towards the end of the TAF period for our northern
terminals such as CLL and UTS as that front approaches. KBL
&&
.MARINE...
Light winds this morning will become southeasterly and southerly
and begin strengthening as pressures lower of W TX this afternoon.
Southerly flow of 10 to 15 knots occasionally 15 to 20 knots will
persist through Tuesday (the stronger winds should be out beyond
20nm). Wednesday the flow backs to the east and southeast and this
should in turn increase the chances for sea fog over the colder
shelf waters. Thursday the low levels slowly moisten further as
winds come back to the south and the intermittent sea fog threat
will likely persist into the weekend. Some differences in the
extended guidance stand out going into Saturday afternoon/night
with either full southeasterly flow or the frontal boundary
stalling near the coast then very slowly lifting north.
Confidence in timing beyond Friday diminishes quickly but overall
expect a warming trend with increasing southerly flow Sunday
possibly approaching SCA.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 69 57 68 50 61 / 0 50 70 60 40
Houston (IAH) 69 58 72 54 67 / 0 20 30 30 30
Galveston (GLS) 64 60 67 57 63 / 0 10 10 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM/AVIATION...KBL
LONG TERM/MARINE/FIRE...35/45