National Weather Service Raw Text Product

494 
FXUS63 KOAX 310526
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1126 PM CST WED JAN 30 2013

.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. WILL MAINTAIN VFR
CONDITIONS THROUGH THE PERIOD WITH SCATTERED TO BROKEN MID CLOUDS.
OPTED TO NOT INCLUDE ANY FLURRIES AT THIS TIME BECAUSE OF
UNCERTAINTYTHAT THEY WOULD ACTUALLY HIT THE TAF SITES...BUT BEST
CHANCES WOULD BE AT KOFK 09-13Z AND KLNK 12-15Z. NORTHWEST WINDS
WILL ALSO BE INCREASING...BECOMING SUSTAINED AROUND 22 KNOTS BY
13-15Z AS ARCTIC SURGE MOVES INTO THE AREA...GUSTING UP TO 30-32
KNOTS. ALSO THOUGHT SOME LOW END VFR CEILINGS COULD DEVELOP
THROUGH THE DAY WITH CONTINUED COLD AIR ADVECTION. GFSLAMP...MAV
AND MET GUIDANCE ALL INDICATE VFR...BUT BUFKIT SOUNDINGS SUGGEST
PERHAPS A SMALL CHANCE OF MVFR CEILINGS. OPTED FOR VFR AT THIS
TIME TO SEE HOW THIS DEVELOPS LATER ON THIS MORNING.

DEWALD

&&

.PREV DISCUSSION... /ISSUED 310 PM CST WED JAN 30 2013/

SHORT TERM...TONIGHT THROUGH SATURDAY

PRIMARY FORECAST CONCERNS ARE TEMPERATURES/WIND CHILLS AND CHANCES 
FOR LIGHT SNOW FROM TONIGHT THROUGH THURSDAY...THEN TEMPERATURES
THURSDAY NIGHT THROUGH SATURDAY.

STORM SYSTEM THAT BROUGHT SNOW LAST NIGHT AND THIS MORNING HAD MOVED 
OFF TO THE EAST. FAIRLY IMPRESSIVE MID AND UPPER TROPOSPHERIC 
STRUCTURE NOTED ON UPPER AIR CHARTS. AT 300 MB ONE JET MAX OF AROUND 
165 KNOTS EXTENDED FROM LAKE SUPERIOR NORTHEASTWARD AND ANOTHER WAS 
NOTED OVER EXTREME SOUTHEASTERN OKLAHOMA. 12 HOUR 500 MB HEIGHT 
FALLS WERE NEAR 200 METERS IN SOUTHWEST MISSOURI. 500 MB 
TEMPERATURES AS COLD AS -34 C WERE NOTED AS FAR SOUTH AS MIDLAND IN 
THE TROUGH THAT STRETCHED FROM THE DAKOTAS TO WEST TEXAS. 850 MB 
TEMPERATURES WERE -10 TO -20 ACROSS THE NORTHERN HALF OF THE PLAINS.

TONIGHT...WINDS SHOULD DROP OFF AT MOST LOCATIONS AS SURFACE RIDGE 
AXIS BUILDS IN OVER THE REGION THIS EVENING. SOME FLURRIES WERE
NOTED AT MID AFTERNOON AND THESE MAY LINGER INTO THE EARLY EVENING.

LATEST MODELS...ESPECIALLY 12Z AND 18Z HIGH RESOLUTION RUNS OF THE
NAM...INDICATE MOISTURE AND A POCKET OF LIFT (MAINLY BELOW 600 MB)
MOVING INTO THE LOCAL AREA FROM THE NORTHWEST AFTER MIDNIGHT.
THIS SHOULD RESULT SOME LIGHT SNOW LATER TONIGHT NEAR AND BEHIND
THE ARCTIC COLD FRONT THAT WILL PUSH ACROSS THE AREA. A SIMILAR
EVENT LAST WEEK RESULTED IN A BAND OF MEASURABLE SNOW OCCURRING.
FOR NOW...THINK AMOUNTS WOULD ONLY BE A FEW TENTHS OF AN INCH...
BUT WILL NEED TO MONITOR THAT FOR LATE TONIGHT AND THURSDAY
MORNING.

OTHERWISE...EXPECT STEADY OR FALLING TEMPERATURES FOR THURSDAY AS
ARCTIC HIGH PRESSURE BUILDS DOWN ACROSS THE PLAINS. DID GO AHEAD
AND ISSUE A WIND CHILL ADVISORY FOR OUR FAR NORTHERN ZONES FROM 
6 AM TO NOON THURSDAY. THAT MAY NEED SOME ADJUSTMENTS IN TIMING
OR AREA AS WE GET CLOSER. COLDEST AIR SETTLES OVER THE AREA
THURSDAY EVENING AND EXPECT LOWS IN OUR WESTERN ZONES WOULD BE
BEFORE 3 AM...WITH SOME MODERATION AFTER THAT. LOWS OVER FRESH
SNOW COVER AND IN THE EASTERN PART OF THE FORECAST AREA MAY BE
LATER IN THE NIGHT WITH STEADY TEMPERATURES BY SUNRISE.

TRIED TO ADJUST HIGHS FRIDAY TO ACCOUNT FOR FRESH SNOW ACROSS MUCH 
OF SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...WITH HIGHS MAINLY 25 TO
30 THERE. HIGHS IN THE 30S ARE EXPECTED FARTHER TO THE WEST AND
NORTHWEST.

MODELS HAVE BEEN SHOWING A SHORTWAVE MOVING ACROSS THE AREA FOR 
FRIDAY NIGHT THE PAST FEW DAYS. AT THIS TIME...DID NOT MENTION ANY 
PCPN (EXCEPT IN A SMALL PART OF SOUTHWEST IOWA)...BUT AS WE GET
CLOSER WE MAY NEED TO ADD SOME LIGHT SNOW. THAT DISTURBANCE SHOULD
MOVE EAST OF THE AREA SATURDAY AFTERNOON WITH MODERATING
TEMPERATURES.

MILLER

LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY.

SIMILAR TO YESTERDAY...DETERMINISTIC MODELS AS WELL AS ENSEMBLES ARE 
IN QUITE GOOD AGREEMENT THE OVERALL LARGE SCALE PATTERN WILL BE 
RELATIVELY STAGNANT SAT-TUE WITH AN UPPER RIDGE SITUATED OVER THE
WRN CONUS/WRN CANADA WITH A BROAD TROF ENCOMPASSING THE ERN CONUS.
BY WED...ECM/GFS/CMC ALL ADVERTISE AN UPSTREAM TROF OFF THE PAC NW
COAST. HOWEVER NOT MUCH AGREEMENT ON HOW AMPLIFIED/POSITIONING OF
CNTRL PLAINS RIDGE.

ISSUE OF INTEREST THEN FOR THE EXT PDS IS ANTICIPATED BNDRY DROPPING 
INTO THE CNTRL PLAINS ON MONDAY ASSOCIATED WITH CLIPPER TYPE SFC 
LOW. MODELS CONSISTENT SHOWING THERMAL ADVECTION VIRTUALLY NON 
EXISTENT WITH THE DRY FROPA AS BULK OF ARCTIC AIRMASS IS PROGGED TO 
REMAIN IN CANADA...NORTH OF THE GREAT LAKES REGION. FOR NOW GOING 
TEMPS LOOK IN GOOD SHAPE WITH HIGHS IN THE LOW/MID 40S...LOWS IN THE 
MID/UPPER 20S. THUS SEE LITTLE REASON TO MAKE ANY CHANGES.  
 
DEE

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND CHILL ADVISORY FROM 6 AM TO NOON CST THURSDAY FOR NEZ011-
     012-015-018.

IA...WIND CHILL ADVISORY FROM 6 AM TO NOON CST THURSDAY FOR IAZ043.

&&

$$