Thursday Morning Update

Thursday, November 21st 2013, 4:44 am
By: Alan Crone

This is posted at 3:45am, Thursday, November 21, 2013.  The following is subject to change.

We're tracking a few thunderstorms this morning across northern OK and southern Kansas.  We're also tracking a major arctic air intrusion set to arrive later this afternoon and tonight across northeastern OK.  Frigid air will follow Friday.  There remains a chance of freezing rain Friday across part of the state.  

First up:  Scattered storms formed last night as expected across portions of west-central and central OK.  These are moving northeast this morning and the stronger storms across western OK may produce some small hail and lightning.  Pockets of moderate to heavy rainfall will be possible with some of the stronger storms.  Most of the thunderstorm activity will move into southern Kansas an out of NE OK by the mid-morning hours.  

Later this afternoon as temps move to near 57 to 60, a few scattered showers or storms may develop across northern OK.  Additional storms will be likely across southwestern and central OK later this afternoon and evening as the front sweeps southward.    

The actual cold front will enter the northwestern part of the state around 11am this morning and move southeastward during the afternoon.  Thunderstorms will attempt to form near this boundary as it approaches the Tulsa area around 3pm to 5pm.  The front should undercut the updrafts near the Northern OK area which will keep storms below severe levels.  The front will accelerate southward and clear southeastern OK by this evening bringing much colder air to the entire region.  

The rest of the Friday forecast is based on a compromise from the GFS-EURO-NAM.  The NAM would support more precipitation over the cold air leading to more ice compared to the others. The NAM is also colder faster across the region.  The other models will bring some light precipitation behind the front Friday morning through midday before ending the precip late Friday afternoon and early evening.  The freezing line will be nearing the northwestern portion of our immediate area tomorrow morning and slowly move southeast by midday to afternoon.   Some winter weather advisories will be required for portions of the state including our neighbors in southern Kansas.  Please check the top of this page for the " Red Bar" with additional up to date information.  

The cold air will remain for the weekend with Saturday afternoon highs in the upper 30s near 40 and mostly to partly cloudy conditions.  Sunday morning will start in the lower 20s and finish around 39 with increasing clouds and a chance of some light precipitation late Sunday evening as an upper level system draws near the area.

A southwestern U.S. low will be nearing the state Sunday night into early next week.  The exact path of the low will be crucial to any winter weather impacts and frankly, it's impossible to know the exact path with any confidence at this hour.  EURO is faster with the system.  GFS is slower.  If the closed low moves directly over the state, some moisture could fall in the form of snow  or a mix for late Sunday night and early morning arrivals, but we anticipate very limited moisture availability for this system next week across the state of Oklahoma.  Much higher moisture content will reside south across the state of Texas where thunderstorm activity will be likely. 

This upper level system will move east of the state Tuesday night into Wednesday providing for improving weather for the Thanksgiving holiday.  Temperatures will be cool and below the seasonal average.  Some extended data support another system nearing the state for the second half of the weekend following Thanksgiving.   

The official high in Tulsa yesterday was 60 recorded at 11:59pm.

The normal daily average high is 58 and the low is 37.

Daily records include a high of79 from 1927 and a low of 18 from 1964.

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Have a super great day. 

Alan Crone