FXUS63 KOAX 082148
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
348 PM CST TUE MAR 8 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY.
PRECIPITATION TYPES AND AMOUNTS TONIGHT...AND WHERE TO KEEP
WINTER WEATHER ADVISORY IN EFFECT...IF ANYWHERE...ARE THE PRIMARY
FORECAST CONCERNS.
STRONG UPPER LOW WAS EJECTING INTO WESTERN KANSAS THIS AFTERNOON
WITH STRONG VORT LOBE ROTATING AROUND THE BASE OF THIS FEATURE
THROUGH THE TEXAS PANHANDLE. THAT VORT LOBE WILL HEAD EAST THEN
NORTHEAST THROUGH MISSOURI AND INTO IOWA OVERNIGHT...AND WILL FOCUS
BULK OF PRECIPITATION AHEAD OF IT. ATTENDANT SURFACE LOW WAS MOVING
THROUGH NORTHERN TEXAS THIS AFTERNOON...WITH WARM FRONT EXTENDING
INTO MISSOURI. CLOSE TO HOME...INVERTED TROUGH WAS NOTED JUST WEST
OF THE CWA AND DELINEATED EAST AND NORTHEAST WINDS IN EASTERN
NEBRASKA AND WESTERN IOWA...AND NORTH WINDS IN CENTRAL NEBRASKA.
TEMPERATURES ACROSS OUR CWA AND POINTS EAST WERE IN THE 30S WITH DEW
POINTS NEAR OR ABOVE FREEZING. AREA OF PRECIPITATION WAS LIFTING
THROUGH OUR SOUTHEAST THIS AFTERNOON. DYNAMIC COOLING WITHIN THIS
PRECIP SHIELD HAD PUSHED TEMPERATURES IN SOUTHWEST IOWA TO FREEZING
AND HELPED PRODUCE SNOW INSTEAD OF RAIN. HOWEVER TEMPERATURES
REBOUNDED BACK INTO THE MIDDLE 30S IN THE WAKE OF THIS PRECIP AREA.
AND MORE POCKETS OF HEAVIER PRECIPITATION WERE NOTED IN NORTHEAST
KANSAS MOVING TOWARD THE SAME AREA. FARTHER TO THE NORTH AND
WEST...ONLY LIGHT RETURNS WERE NOTED ON RADAR WITH SPRINKLES THE
MOST COMMON PRECIPITATION.
QUESTIONS WITH THIS FORECAST ARE WHERE IT WILL SNOW...AND IF
SIGNIFICANT ACCUMULATIONS CAN BE REALIZED GIVEN WARM AIR AND GROUND
TEMPERATURES. FIRST OF ALL...HEAVIEST PRECIPITATION IN THE SOUTHEAST
WILL OCCUR THIS AFTERNOON BEFORE LIFTING TO THE NORTHEAST THIS
EVENING. EXPECT RAIN AND SNOW...WITH SNOW OCCURRING DUE TO DYNAMIC
COOLING REGIME WHICH SHOULD END AS PRECIP BAND MOVES AWAY. WARM
TEMPERATURES AND REBOUNDING TEMPERATURES WILL LIMIT SNOW AMOUNTS TO
ONLY AND INCH OR SO...AND MAINLY IN GRASSY SURFACES. OCCASIONAL
LIGHT RAIN WILL FOLLOW...AND WILL EVENTUALLY CHANGE TO SNOW AGAIN
LATER TONIGHT.
FROM THE INTERSTATE 80 CORRIDOR AND TO THE NORTHWEST...SATELLITE
LOOPS AND RADAR TRENDS...COUPLED WITH AN AVERAGE OF MODEL
FORECASTS...SUGGEST MID/UPPER LEVEL DEFORMATION BAND ON NORTHWEST
SIDE OF APPROACHING UPPER LOW WILL SET UP JUST NORTHWEST OF THE
INTERSTATE. MOST LIKELY FROM NEAR COLUMBUS TO TEKAMAH TO ONAWA.
ENHANCED TOTAL PRECIPITATION IS POSSIBLE WITHIN THIS BAND GIVEN
LONGER DURATION OF PRECIP. TEMPERATURES IN THE WEST WILL DROP TO OR
BELOW FREEZING FIRST AS INVERTED TROUGH WORKS EAST...THEN A GRADUAL
CHANGE FROM RAIN/SNOW TO ALL SNOW IN THE EAST IS EXPECTED DURING THE
EVENING. FARTHER TO THE NORTHWEST...ONLY LIGHT SNOW IS EXPECTED AS
BEST LIFT WITH UPPER LOW IS TO THE SOUTHEAST OF THIS AREA.
MODEL AND HPC FORECASTS SUGGEST ONLY A COUPLE OF TENTHS OF LIQUID
PRECIP IS EXPECTED IN OUR SOUTHEAST...WITH A TENTH OF AN INCH OR
LESS IN THE WEST AND NORTHWEST. MUCH OF THE PRECIP WILL STAY IN
LIQUID FORM...AND HOW MUCH WILL GO TO SNOW IS STILL IN QUESTION.
HOWEVER...TAKING EVEN THE HIGHEST MODEL QPF...STILL ONLY LOOKING AT
A COUPLE OF INCHES OF SNOW AT A 10 TO 1 RATIO.
SINCE WE ALREADY HAVE A WINTER WEATHER ADVISORY GOING...AND COULD
SEE A COUPLE OF INCHES OF SNOW IN MANY PARTS OF THE CWA...WILL KEEP
MUCH OF THAT GOING FOR NOW. HOWEVER WILL TRIM THE SOUTH WHERE TEMPS
ARE PLENTY WARM...AND IN THE NORTHWEST WHERE ONLY LIGHT AMOUNTS OF
SNOW ARE EXPECTED. THIS IS ALSO IN LINE WITH ADVISORIES FROM
SURROUNDING OFFICES.
MOVING ON. PRECIPITATION WILL BE MOVING OFF TO THE EAST WEDNESDAY
MORNING. COULD SEE LINGERING LIGHT SNOW IN THE MORNING EAST SO WILL
KEEP SMALL CHANCES THERE. CLOUDS WILL START TO CLEAR FROM WEST TO
EAST IN THE AFTERNOON...HELPING TO PUSH TEMPS INTO THE 30S MOST
AREAS.
HIGH PRESSURE WILL SETTLE OVER THE PLAINS WEDNESDAY NIGHT AND
THURSDAY. PLENTY OF SUNSHINE THURSDAY WITH SOUTHERLY FLOW RETURNING
WILL HELP WARM TEMPS INTO THE 40S FOR MUCH OF THE AREA. THEN EVEN
WARMER FRIDAY AS SOUTHWEST FLOW IS DOMINANT AS LOW PRESSURE SWEEPS
THROUGH THE NORTHERN PLAINS. 850 TEMPS PUSH 10-12C...SUGGESTING SOME
60S ARE POSSIBLE IN OUR SOUTHWEST.
DERGAN
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
OVERALL 12Z GFS/00Z CMC RUNS SIMILAR WITH THE 00/08Z ECM THE
OUTLIER. HOWEVER ALL AGREE LARGE SCALE FLOW WILL BE WAVY ACROSS THE
CONUS DURING THE FCST PD WITH A PUSH OF CANADIAN COLD AIR INTO THE
LOWER 48 EARLY THIS WEEKEND ON BACKSIDE OF GREAT LAKES SFC LOW. CAA
ADVERTISED TO DRIVE FAR ENOUGH SOUTH INTO THE CNTRL PLAINS SUCH THAT
AM ANTICIPATING TEMPS GRADUALLY FALLING JUST BELOW NORM THIS
WEEKEND. OTHERWISE PCPN CHANCES RETURN SUNDAY IN RESPONSE TO
SHORTWAVE TROF CROSSING THE PLAINS. IMPLIED LIFT PER MID/UPPER QVECT
CONVG FITTING REASONABLE WELL WITH PLACEMENT OF MAX OMEGA. OVERALL
MOISTURE TO TAP INTO NOT ALL THAT IMPRESSIVE...BUT THE GFS DOES SHOW
MOISTURE ADVECTING(PER PWS) NWD THRU TX/OK/KS AND SHOULD BE ENOUGH
REACHING THE CWA TO ALLOW FOR LIGHT PCPN ACTIVITY THRU SUNDAY NIGHT.
EXPECT PCPN TYPE MAINLY A RA/SN MIX.
DEE
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
SOUTHERN PLAINS LOW WILL LIFT NORTHEAST TONIGHT SPREADING MIX OF
RAIN AND SNOW ACROSS THE REGION. MVFR TO IFR CONDITIONS EXPECTED
THROUGH THE PERIOD WITH KOFK EXPECTED TO SEE MORE LIMITED PERIOD OF
SNOW PRIOR TO 06Z. PRECIP ENDING AFTER 06Z AT BOTH KLNK AND KOMA.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR NEZ015-018-
032>034-044-045-051>053-066>068.
WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR NEZ030-031-
042-043-050-065-078.
IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR IAZ043-055-
056-069-079-080-090-091.
&&
$$