Area Forecast Discussion
Issued by NWS Tulsa, OK

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000
FXUS64 KTSA 242334
AFDTSA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
534 PM CST WED DEC 24 2014

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
ONGOING MVFR CEILINGS ACROSS WESTERN AR WILL CONTINUE TO PUSH
EASTWARD THIS EVENING W/ VFR CONDITIONS EXPECTED TO PREVAIL FOR
ALL SITES THEREAFTER. STRONG WINDS WILL DEVELOP AFTER SUNRISE THURS.

&&

.PREV DISCUSSION... /ISSUED 306 PM CST WED DEC 24 2014/

DISCUSSION...

UPPER TROUGH IS LIFTING OUT OF THE PLAINS THIS AFTERNOON...AND
THUS PRECIP HAS ENDED AND CLOUDS ARE CLEARING OUT FROM WEST TO
EAST. THIS TREND WILL CONTINUE INTO THE EVENING WITH CLEAR SKIES
EXPECTED OVERNIGHT. WEST WINDS WILL SUBSIDE AS WELL...BUT THERE
WILL NOT BE MUCH BREAK BEFORE SOUTH WINDS KICK IN.
NEVERTHELESS...TEMPS SHOULD DROP DOWN INTO THE 20S TO NEAR 30
TONIGHT. INCREASING DOWNSLOPE FLOW IN ADVANCE OF THE NEXT UPPER
SYSTEM WILL INDUCE LEE TROUGHING AND A TIGHTENING PRESSURE
GRADIENT OVER OUR REGION TOMORROW. BY AFTERNOON...WINDS WILL BE
APPROACHING ADVISORY CRITERIA...AS GUSTS AT THE TYPICAL WINDY
SPOTS ACROSS NE OK GET CLOSE TO 40 MPH. I HAVE HELD OFF ON ISSUING
A HEADLINE BASED ON A COUPLE OF LIMITING FACTORS...ONE...THE NAM
IS SHOWING A FAIRLY SHALLOW MIXING DEPTH TOMORROW AS THE INVERSION
OFF THE DECK INTENSIFIES DUE TO THE DOWNSLOPING...AND SECOND...THE
LATEST NAM12 WIND FORECAST SHOWS 20 KT BARBS OVER OUR AREA. WOULD
BE MORE CONFIDENT IN GOING WITH AN ADVISORY IF THIS WAS A TAD
STRONGER. WILL LET THE MIDSHIFT MAKE THE FINAL CALL. THE FIRE
DANGER WILL BE VERY HIGH REGARDLESS...AND A FIRE DANGER STATEMENT
WILL BE ISSUED FOR TOMORROW AFTERNOON.

THE NEXT UPPER SYSTEM COMING IN FROM THE PACIFIC AS I TYPE WILL
DIVE DOWN INTO THE DESERT SOUTHWEST BEFORE SLIDING EAST OVER THE
PLAINS BY THE WEEKEND. THE CONCOMITANT COLD FRONT WILL SLIDE DOWN
THE PLAINS IN ADVANCE OF THE SYSTEM FRIDAY NIGHT INTO SATURDAY. QG
AND FRONTOGENETIC FORCING WILL INCREASE DURING THIS TIME
FRAME...WITH THE ECMWF/CANADIAN/GFS SHOWING POST FRONTAL PRECIP.
THE 12Z NAM WAS A DRY OUTLIER...HOWEVER THE 18Z MAY BE SHOWING
SIGNS OF TRENDING IN THAT DIRECTION. REGARDLESS...IT APPEARS THE
BULK OF THE PRECIP WILL BE FALLING IN THE WARMER AIR FROM
SOUTHEAST OK UP INTO WESTERN AR WHERE IT WILL BE MAINLY RAIN. THE
AIRMASS BEHIND THE FRONT WILL NOT BE TRUE ARCTIC
AIR...NEVERTHELESS LAYER TEMPS ACROSS NORTHEAST OK INTO FAR
NORTHWEST AR ARE FORECAST TO GET COLD ENOUGH TO SUPPORT A WINTRY
MIX...ALTHOUGH PRECIP AMOUNTS ON THE NORTHWEST FRINGE WILL BE THE
LIGHTEST. THUS...WHILE IT IS POSSIBLE THAT THIS MAY BECOME AN
ADVISORY EVENT AT SOME POINT...A BIG WINTER STORM THIS WILL NOT
BE.

THE MODEL CONSENSUS FROM THE 12Z RUNS THIS MORNING ALSO IS
TRENDING TOWARD ENDING PRECIP QUICKLY BY SATURDAY EVENING AND I
HAVE TRENDED THE FORECAST THAT WAY AS WELL. A SECONDARY WAVE
ROUNDING THE BASE OF THE EJECTING TROUGH WILL LIFT ENE OUT OF OLD
MEXICO ON SUNDAY. AGREEMENT TODAY WAS EXCELLENT AMONGST THE
CANADIAN/ECMWF/GFS THAT THE ASSOCIATED PRECIP WILL STAY SOUTH OF
THE RED RIVER AND THUS SUNDAY WILL BE A DRY FORECAST.

THEN WE GET TO NEXT WEEK. MODEL RUN TO RUN CONSISTENCY IS QUITE
POOR AT THIS TIME RANGE...AS THE GFS AND ECMWF HAVE NOW FLOPPED
BACK TO A SOLUTION THEY HAD 2 DAYS AGO...IE SIGNIFICANT HEIGHT
FALLS DOWN OVER THE DESERT SOUTHWEST. THE 12Z CANADIAN IS SHOWING
BASICALLY WHAT THE ECMWF AND GFS WERE SHOWING YESTERDAY...DRY NW
FLOW ON THE WEST SIDE OF BROAD CYCLONIC FLOW OVER THE EASTERN
2/3RDS OF THE NATION. IT IS CLEAR THAT THE ECMWF AND GFS ARE
STRUGGLING WITH WHAT TO DO WITH JET STREAM ENERGY THAT IS BASICALLY
DIVING STRAIGHT SOUTH OUT OF WESTERN CANADA...AND THE UPSTREAM
RIDGING OVER ALASKA. NO MATTER WHAT SOLUTION YOU BELIEVE...IT IS
GOING TO GET COLD NEXT WEEK...WITH A TAP OF TRUE ARCTIC AIR THAT
CAN BE TRACED BACK UP TO THE YUKON AND NORTHWEST TERRITORY.
HOWEVER...CONFIDENCE IS LOW REGARDING ANY PRECIP POTENTIAL TO GO
ALONG WITH THIS COLD AIR AND HAVE THUS ELECTED TO MAINTAIN THE
GOING DRY FORECAST FOR THE EARLY TO MIDDLE PART OF NEXT WEEK.

LACY

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   30  58  44  55 /   0   0   0  20
FSM   29  56  40  57 /   0   0   0  20
MLC   30  57  46  57 /   0   0   0  20
BVO   24  57  41  54 /   0   0   0  20
FYV   26  51  40  54 /   0   0   0  20
BYV   28  51  40  54 /   0   0   0  20
MKO   28  57  43  57 /   0   0   0  20
MIO   28  55  42  55 /   0   0   0  20
F10   30  57  45  56 /   0   0   0  20
HHW   30  58  43  57 /   0   0   0  20

&&

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

$$

AVIATION...07





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