Southern Plains winter wx thread (2009-2010)

[Extremeweatherguy]

Check out the MCS that may be moving towards Oklahoma. Talk about heavy precip.

That would be crazy if it made it here!

[BlueIce]

Just FYI: Centerpoint Energy is enroute from Houston with a convoy to assit those in OK.

We may need it, glad OGE has contacted Centerpoint to help us out.

To monitor the potential power problems check out OGE's system watch.
http://public.oge.com/systemwatch/

[Extremeweatherguy]

I am really impressed by the temperatures right now! The models last night were predicting us to reach freezing right about now, but instead we reached freezing several hours ago and are now in the upper 20s. This is not good news at all in terms of ice accumulation. Ice will build up much more quickly at 28F vs. 32F.

[srainhoutx]

Check your PM's EWG.

[BlueIce]

I-40 Eastbound near Elk City is now closed due to a semi that has flipped and blocked the entire highway at this point.

[srainhoutx]

ZCZC NFDSPENES ALL
SPENES
TXZ000-OKZ000-
.
SATELLITE PRECIPITATION ESTIMATES..DATE/TIME 01/28/10 1509Z
SATELLITE ANALYSIS BRANCH/NESDIS---NPPU---TEL.301-763-8678
LATEST DATA USED: GOES-12: 1445Z DS
.
LOCATION...W/CENTRAL TEXAS...S/EXTREME SW OKLAHOMA...
.
ATTN WFOS...FWD...OUN...EWX...SJT...LUB...MAF...
ATTN RFCS...ABRFC...WGRFC...
.
EVENT...MOD-HVY RAINFALL
.
SATELLITE ANALYSIS AND TRENDS...WV IMAGERY SHOWS AN ELONGATED UPPER LVL
S/WV TROF ROTATING NEWD FROM MX WITH TWO SMALL EMBEDDED VORTS. A WIDE
AREA OF DIFFLUENT FLOW ALOFT RUNNING FROM NE NM TO ERN OK/CENTRAL TX IS
EVIDENT IN WV AS WELL. IR IMAGERY HAS DEPICTED COOLING CLOUD TOPS TO -63C
WITHIN THIS DIFFLUENT FLOW OVER THE PAST 1-2 HRS AS CNVTN HAS INTENSIFIED
ACROSS PARTS OF W/W CENTRAL TX AND THE SRN TX PANHANDLE. MOST PROMINENT
IS A THIN LINE OF CNVTN/HVY RAINFALL FROM BORDEN TO IRION COUNTIES WHILE
ELSEWHERE RAINRALL ACROSS W CENTRAL TX..RAINFALL HAS BEEN MORE MOD IN
INTENSITY WITH PRECIP CHANGING OVER TO FREEZING RAIN N OF A LINE ROUGHLY
FROM KHOB IN NM PASSING JUST S OF LBB TO EXTREME SW OK.
.
STRONGEST SFC MOISTURE CNVG..CURRENTLY CENTERED JUST W OF SJT..HAS
BEEN CONCENTRATED JUST AHEAD OF A SFC LOW OVER W TX. VIS/RADAR IMAGERY
BOTH SHOW NEW CNVTN BEGINNING TO DVLP OVER PARTS OF TERRELL/CROCKETT
COUNTIES WITH ADDTL TSTORMS LIKELY TO FOLLOW NEWD FROM SRN PRESIDIO/SRN
BREWSTER COUNTIES. VIS SHOWS SVRL OVERSHOOTING TOPS ASSCD WITH THIS
GROWING CNVTN..INDICATING STRONG POTENTIAL FOR HVY RAINFALL AS THESE
CELLS MATURE. 1" OR GREATER PW VALUES BEING LIFTED NWD BY SRLY/SSERLY LL
FLOW WILL CONTINUE TO FEED INTO THE GROWING TSTORMS. IN THE NEXT 1-1.5
HRS..THE GREATEST FF THREAT WILL LIKELY BE OVER CROCKETT/IRION/WRN TOM
GREEN/STERLING/GLASSCOCK/REAGAN COUNTIES SINCE THE MAIN LINE OF CNVTN
IS CURRENTLY OR HAS RECENTLY PASSED THROUGH THOSE COUNTIES AND NEW
GROWING CNVTN IS/WILL AGAIN CROSS THOSE SAME AREAS. THE FF THREAT WILL
LIKELY THEN SPREAD OUT TO THE NE FROM THOSE COUNTIES. RAINRATES AROUND
AND SOMETIMES ABOVE 1"/HR WILL BE POSSIBLE ACROSS THE ABOVE DESCRIBED
AREA. PLEASE SEE WEB ADDRESS SHORTLY FOR GRAPHIC ANALYSIS.
.
SEE NCEP HPC DISCUSSION AND QPF/S FOR FORECAST.
....NESDIS IS A MEMBER OF 12 PLANET....
.
SSD/SAB WEB ADDRESS FOR PRECIP ESTIMATES:
HTTP://WWW.SSD.NOAA.GOV/PS/PCPN/
...ALL LOWER CASE EXCEPT /PS/PCPN/
.
LAT...LON 3472 9923 3400 9734 3120 9765 2784 10360 2944 10489
3130 10271 3319 10279

[Extremeweatherguy]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
939 AM CST THU JAN 28 2010

.UPDATE...
WILL BE EXPANDING THE WINTER STORM WARNING FARTHER SOUTH AS COLD
LOW-LEVEL AIR CONTINUES TO SPREAD SOUTH... WHICH WILL LEAD TO
CHANGE TO FREEZING RAIN LATE THIS MORNING OR THIS AFTERNOON ACROSS
AREAS JUST SOUTH OF THE CURRENT WARNING. AS COLD AIR CONTINUES TO
SPREAD SOUTH AND DEEPEN... WE ARE GETTING REPORTS OF MIX OR
CHANGE-OVER TO SLEET IN HOBART AND THE NORTHWEST OKC METRO. DRY
LOW-LEVEL AIR IS FILTERING INTO THE AREA /DEWPOINT DEPRESSIONS
ARE 5 TO 15 DEGREES ACROSS MUCH OF CENTRAL AND NORTHERN OKLAHOMA
IN THE COOL AIRMASS/... WHICH SHOULD CONTINUE TO COOL THE NEAR-
SURFACE COLD LAYER AND MAY ALLOW MORE AREAS TO MIX WITH OR CHANGE
TO SLEET THIS AFTERNOON AS OPPOSED TO FREEZING RAIN.

WE ARE PLANNING TO LAUNCH 3-HOURLY SOUNDINGS TODAY TO ASSESS THE
THERMODYNAMICS OF THE AIRMASS. PARTIAL DATA FROM THE 15Z SOUNDING
HAS ALREADY BEEN SENT. .26.

This would be GOOD news! Hopefully we do changeover to sleet sooner rather than later and can avoid this freezing rain disaster!

[Peanut432]

Why is there no Ice storm warning? Whats the criteria?

[Extremeweatherguy]

Why is there no Ice storm warning? Whats the criteria?

This meets the ice storm warning criteria, however since sleet and snow is also possible during the event, and not only freezing rain, a winter storm warning is a better fit for the situation.

[Extremeweatherguy]

The 12z NAM looks a little snowier for tomorrow than first thought. We will have to watch this closely, as after the ice storm today, there might actually be a moderate to significant snowfall tomorrow. The latest NAM is currently depicting about 6" of snow for both OKC and OUN during the day tomorrow, which if it plays out, would be much more than first thought.

[Peanut432]

According to the AMA AFD from this mourning the storm has slowed down more.

[slowpoke]

According to the AMA AFD from this mourning the storm has slowed down more.

slowed down as in distance or slowed down as in dieing out?

[Peanut432]

Slowed down as in movement.

[slowpoke]

hmmm that isnt good....

[Weatherdude20]

Slowed down as in movement......

[msstateguy83]

32 @ my house in w.falls now...

[Peanut432]

Ice storm warning for LBK. I have about a 1/4 in of ice at my house already if I was to quess

[wx247]

On lunch break here at school. My students have been wound up today for sure. I am worried some about dry air. Otherwise, all systems go here later today.

[cycloneye]

Impressive winter storm that covers a big chunk of the Southern Plains.

[srainhoutx]

MESOSCALE DISCUSSION 0074
NWS STORM PREDICTION CENTER NORMAN OK
1218 PM CST THU JAN 28 2010

AREAS AFFECTED...CENTRAL...SRN...NERN AND N-CENTRAL OK INTO EXTREME
NWRN AR

CONCERNING...WINTER MIXED PRECIPITATION

VALID 281818Z - 282215Z

A PROLONGED PERIOD OF FREEZING RAIN IS EXPECTED TO OCCUR ACROSS MUCH
OF CENTRAL OK THIS AFTERNOON...WHILE ALSO SPREADING TOWARD
E-CENTRAL/NERN OK AND EXTREME NWRN AR BY LATE AFTERNOON/EARLY
EVENING. ACROSS N-CENTRAL OK...DRY LOW LEVEL AIR WILL EVENTUALLY
MOISTEN WITH TIME...LEADING TO SLEET TRANSITIONING TO SNOW TOWARD
00Z. FARTHER S OVER S-CENTRAL OK...DRY AIR MAY ADVECT INTO THE AREA
DURING THE AFTERNOON...CAUSING THE WET BULB ZERO LINE TO SHIFT SOUTH
TOWARD THE RED RIVER...WHICH WOULD INCREASE THE PROBABILITY FOR
SIGNIFICANT FREEZING RAIN.

AT 17Z...SFCOA DATA INDICATED THE WET BULB ZERO LINE EXTENDED FROM
ROUGHLY FSM/W-CENTRAL AR TO A LOCATION IMMEDIATELY S OF FSI IN
SWRN/S-CENTRAL OK. SURFACE OBSERVATIONS SUGGEST THAT NELY WINDS
ACROSS MUCH OF OK WILL CONTINUE TO USHER IN DRY LOW LEVEL AIR TOWARD
S-CENTRAL OK...WHICH WOULD FAVOR A SWD PUSH OF THE WET BULB ZERO
LINE TOWARD THE RED RIVER. MEANWHILE...SIGNIFICANT WARM AIR ABOVE
THE SURFACE CONTINUES TO BE DRAWN INTO THE LOW LEVEL CYCLONIC
CIRCULATION ATTENDANT TO THE SWRN CONUS UPPER TROUGH...WITH A
PROMINENT WARM NOSE /5-6 DEG C/ CENTERED NEAR 850 MB PER 15Z OUN
SPECIAL SOUNDING. AS THE SHIELD OF PRECIPITATION ASSOCIATED WITH THE
WARM CONVEYOR BELT CONTINUES TO SPREAD NWD INTO OK...MODEL FORECAST
SOUNDINGS INDICATE THERMODYNAMIC PROFILES WILL REMAIN FAVORABLE FOR
FREEZING RAIN ACROSS MUCH OF CENTRAL OK...PERHAPS SPREADING SWD
TOWARD THE RED RIVER GIVEN THE RECENT TRENDS IN SURFACE
OBSERVATIONS. FORECAST SOUNDINGS ALSO SHOW LAPSE RATES STEEPENING
TOWARD 00Z OVER S-CENTRAL/CENTRAL OK...WITH A FEW HUNDRED J/KG OF
MUCAPE ROOTED NEAR 700 MB SUGGESTIVE OF CONVECTIVELY ENHANCED
PRECIPITATION RATES.

OTHERWISE...AS THE 40-50 KT S-SELY LLJ BEGINS TO SHIFT EWD WITH THE
EMERGING UPPER TROUGH TOWARD EVENING...HEAVIER PRECIPITATION RATES
WILL BEGINS TO SPREAD ACROSS E-CENTRAL/NERN OK INTO EXTREME NWRN
AR...AT WHICH POINT MODEL GUIDANCE DEPICTS RAPID WET BULB COOLING
AND MOISTENING IN THE BOUNDARY LAYER...RESULTING IN THE ONSET OF
FREEZING PRECIPITATION PERHAPS MIXED WITH SLEET. FARTHER W FROM
CENTRAL INTO N-CENTRAL OK...FREEZING RAIN MAY TRANSITION TO SLEET
MORE QUICKLY DUE TO COOLER 850 MB TEMPERATURES...WITH SNOW BECOMING
MORE PROBABLE TOWARD 00Z PER SREF GUIDANCE.

..GARNER.. 01/28/2010