Tuesday Morning Update

Tuesday, December 18th 2012, 5:23 am
By: Alan Crone

We expect a wonderful weather day with sunshine and highs in the mid-60s.  A fast moving system arrives Wednesday night with much colder air into Thursday.  

Well, where to begin.  There's no doubt in my mind that you have heard about or read about the possibility of a major storm system approaching during the Christmas time period.  Let's get this out of the way quickly:  there is absolutely no way we can say with any confidence this morning whether or not we'll see snow with the Christmas time period system. It's simply too early in the forecast process.  The data has already changed a few times during the past 2 days regarding the time period and the position of the main features of interest.  One model brings the system into the area on Christmas Day, and the other delays the system until the day after Christmas. The computer model data will be analyzed during every run and we'll continue to watch this time period carefully and make statements when appropriate.  If one takes the latest data as absolutely true, we would have a round of rain-storms followed by cold enough air to support wintry precip including a pretty good shot of snow.  Again, we're way too early in the game to discuss any specifics.  At the same time, we also understand the need to get this information out as early as possible due to Christmas travel plans. We encourage you to remain aware of this time period, and we'll make adjustments to the forecast as the period draws closer. 

The first issue for our short term forecast is a fast moving system arriving Wednesday night into Thursday morning.  A strong and broad upper level system currently across the Pac northwest will move eastward today and tomorrow.  A surface area of low pressure will develop across northwestern OK (or near the vicinity) either tonight or Wednesday.  This will allow strong southerly winds to move across the southern plains and OK by Wednesday.  The fire danger will be very high during this period before low level moisture begins to transport rapidly across Eastern OK Wednesday afternoon and evening.  A dry line to the west will slide eastward Wednesday afternoon with a surface cold front catching the dry line around 8pm to 10 pm Wednesday evening.  At this point, a few storms may be a possibility across extreme eastern OK or western Arkansas.  A few of these storms could be severe with wind  and hail the main threat.  The upper air profile seems to support a squall line type feature as the storms mature with time into pre-dawn Thursday.  Our chances for thunderstorm activity in Tulsa remain around 20% but locations along and east of highway 69-75 will be in the running for a 30 to 40% pop.  This window for possible storm formation will be relatively small from 6pm to midnight.  

As the upper level trough slides across the southern plains, snow will begin to develop across portions of extreme Eastern Colorado, central Kansas, northern Missouri, and into portions of the Midwest.  Measurable snow is likely along portions of the I-70 corridor of central and eastern Kansas.  The snow drought in Chicago (289 days without measurable snow as of today) should end Thursday with some snowfall in the or near the big city.  

We may see a very small window for some light flurries or possibly some slight snow showers across extreme northern OK along and north of the highway 412 corridor between midnight and pre-dawn Thursday.  No accumulation will be expected but a minor dusting is possible across far NE OK.   The odds of any real snow in Tulsa remain near 20% chance.  Remain aware of the possibility but the big issue will be the much colder air Thursday along with strong northwest winds.  Temps for the day will not move out of the mid-40s and strong northwest winds will knock the wind chill values down into the upper teen's low lower 20s.  

Before the system arrives Wednesday night, there is a very good possibility of strong south to southwest winds. This veering profile of the winds will also act to push the low level moisture slightly eastward Wednesday evening.  As the winds veer from the west Wednesday evening behind the dry line and before the cold front arrives, blowing dust from west Texas and western OK may have a chance to move into our area.  It's a very high likelihood that blowing dust will be a big problem across the western half of the state Wednesday afternoon.  Just how far east the dust may move before the cold front arrives is a big guess at this point.  

Temps Friday into the weekend will be in the 50s for highs and morning lows in the upper 20s and lower 30s.  The weekend appears very pleasant and mild before the possibility of the big system approaching early next week begins to dominate the forecast.


Yesterday's afternoon high was 56 recorded at 3:20pm.

The normal daily average is now 48 for the high and a low of 29.

Our daily records include a high of 72 recorded in 1939 and a low of 4 recorded in 1964.


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You'll hear me discussing our weather on the radio this morning with Dan Potter and KRMG morning news.  I'll also be on numerous Radio Oklahoma Network stations throughout the morning.


Thanks for reading the Tuesday morning weather discussion.

Have a super great day.

Alan Crone