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Office: TSA

FXUS64 KTSA 211045
AFDTSA

Area Forecast Discussion
National Weather Service Tulsa OK
545 AM CDT Tue Aug 21 2018

...UPDATE...

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.

Main aviation concern is the potential for MVFR ceilings this
morning at the NW AR terminals and perhaps BVO as well. These
ceilings should lift late morning into early afternoon with VFR
conditions expected thereafter. VFR conditions will prevail at the
remaining terminals through the period. Toward sunrise Wednesday,
there is a nonzero chance of showers or thunderstorms mainly at
BVO, but those chances are well below mentionable levels. Chances
increase after 12Z Wednesday.

&&

.PREV DISCUSSION... /Issued 403 AM CDT Tue Aug 21 2018/

DISCUSSION...
The relatively cool August weather will persist for a couple more
days before summertime heat returns for the weekend into next
week. Mainly late night and morning shower and thunderstorm
chances will exist from late tonight through Friday morning as
upstream MCS activity attempts to push into mainly the northern
part of our area along the southern edge of the stronger mid level
flow. The resultant clouds will help hold temperatures down
through Thursday. By this weekend into next week, an upper ridge
takes hold, with hot and humid weather returning, although daytime
temperatures will still be somewhat modulated by the copious
amounts of rain that have fallen recently in many locations.

Stayed close to guidance temperatures the next couple days.

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&

$$


AVIATION.....22



Office: OUN FXUS64 KOUN 211054 AFDOUN Area Forecast Discussion National Weather Service Norman OK 554 AM CDT Tue Aug 21 2018 .AVIATION... TAFS 2112/2212... VFR conditions are expected through the period. A north wind will become east and southeast this afternoon/night. Mid and high clouds will increase across at least northern Oklahoma this evening/night with widely scattered showers and a thunderstorm across northwest Oklahoma after 4Z. && .PREV DISCUSSION... /issued 338 AM CDT Tue Aug 21 2018/ DISCUSSION... A mid and upper level ridge center over New Mexico, will build eastward today and tonight. Meanwhile, surface winds will become east to southeast across western Oklahoma today and the rest of the area tonight. Upslope flow over eastern Colorado and a weak upper air disturbance will result in scattered afternoon showers and thunderstorms. Widely scattered showers and a few storms should reach mainly northwest Oklahoma during the late evening and overnight, but limited instability should reduce coverage farther east. Afternoon and evening showers and storms are expected to develop again Wednesday. Better coverage of showers and storms should be across Kansas where the low to mid level flow will be stronger. A trough is forecast to move across the northern Plains late Thursday into Friday. This may result in widely scattered showers and thunderstorms mainly across the northern third/half of Oklahoma. Dry, breezy and hot weather is expected over the weekend/early next week as the mid level ridge builds northward and eastward. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 86 66 88 68 / 0 10 10 20 Hobart OK 92 69 91 72 / 0 10 10 10 Wichita Falls TX 94 69 93 74 / 0 0 10 0 Gage OK 87 65 86 68 / 0 40 40 40 Ponca City OK 86 66 79 64 / 0 40 50 60 Durant OK 91 68 91 71 / 0 0 10 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$
Office: AMA FXUS64 KAMA 211131 AFDAMA Area Forecast Discussion National Weather Service Amarillo TX 631 AM CDT Tue Aug 21 2018 .AVIATION... 12Z Issuance...VFR conditions unless storms hit GUY and DHT, then cigs or vsby may be lower. If storms happen, it would hit DHT starting after 00Z and at GUY after 02Z, but confidence is middle of the road. Winds will be southerly and moving more southeasterly after 00Z. If storms do happen, any outflows could change the wind direction. Will monitor and update when more confidence is build. Beat && .PREV DISCUSSION... /Issued 353 AM CDT Tue Aug 21 2018/ DISCUSSION... The northerly flow yesterday, that allowed for smoke from the fires all the way up in CA/OR/WA to be transported across the northern Rockies and then down the great plains, will become more northwesterly today. The flow at the lower levels will become more south to southeasterly today due to a lee surface low setting up. This southerly flow should aid in the dispersal of the smoke by late morning to early afternoon. Northwest flow today will transition to more of a westerly flow later in the evening and overnight as an upper level trough from the northwest will help suppress the ridge off over the AZ/NM area. Models continue to hang on to a shortwave that looks to move across the northern Panhandles around 7pm this evening. This could be a hit or miss scenario for the central and northern Panhandles, as depending on the track of the shortwave and the timing, it could impact the southern CO/KS area, and have limited impact the the OK Panhandle, with litter to no impact in the TX Panhandle. Deterministic models seem to favor the impacts the be in the TX/OK Panhandle area, while the CAM's want to favor a more northerly progression of the activity. Some things to note for today, conditional instability ahead of the main shortwave, ML CAPE ranges from 1000-2000 J/kg. Helicity values are fairly decent given the southeasterly winds at the surface and the westerly winds aloft. Storms could be strong to severe with wind and hail being the primary threat, but wont rule out a low end tornado threat. The LCL's are pretty high in the 5 to 6kft range. With a minimal cap later in the evening storms should line out and be more elevated in nature, becoming more of a wind threat. Flow will be more westerly on Wednesday into Thursday, but monsoon moisture will still be transported over the area, as well as the potential for other shortwaves to move across. This will keep the chances for storms going, mainly for the central and northern Panhandles. Storms could be strong to possibly severe as well on Wednesday afternoon and evening, with wind and hail being the main threat. As the upper level trough slowly progresses across the northern CONUS, the high will remain suppressed to the southeast TX area, continuing the westerly flow across the Panhandles. As a result showers and storms will be possible again on Thursday. As we head into the end of the work week and the weekend, the high that was suppressed to the southeast will strengthen across the southern CONUS, due to the exit of the trough the northeast. Still a little difficult to tell if we will be close enough to the center of the high, to remain under mostly subsidence and stay dry the entire time, but do expect that if the high shifts far enough east, return moisture from the southwest will likely impact the Panhandles, allowing for a better chance for precipitation in the extended. As it stands now holding onto a dry pattern from Friday onward. Something important to note, being on the back side of the high will also transport warmer/hot temperatures to the area, the Palo Duro Canyon floor is forecast to be right around 100 degrees Thursday to the end of the forecast period. All other areas can expect upper 90s to near 100 as well for the extended period. Weber AVIATION... 06Z Issuance...VFR conditions expected but northern sites may see storms after 00Z that may lower conditions. Winds are turning clockwise from easterly to southerly with some gusts to 20kts. Smoke causing low vsby should start clearing up by morning. Beat && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 16/89