FXUS63 KOAX 180918
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
318 AM CST FRI FEB 18 2011
.DISCUSSION...
SHORTWAVE ENERGY THAT DROVE COLD FRONT ON GUSTY NW WINDS THROUGH
FORECAST AREA LATE THURSDAY WAS LIFTING ACROSS MN ARROWHEAD EARLY
FRIDAY MORNING. UPPER RIDGING IS FORECAST ACROSS THE AREA INTO
SATURDAY AS AN UPPER TROUGH DIGS ALONG WEST COAST BEFORE COMING
INLAND THROUGH THE WEEKEND. DEPARTING UPPER TROUGH AND UPPER
HEIGHTS BEGINNING TO RISE...HAS BOTTLED THE COLDEST AIR NORTH OF
NEBRASKA/SW IA WITH SFC FLOW MOSTLY WRLY. ALTHOUGH SOME COOLER
AIR WILL CONTINUE TO LEAK INTO THE FORECAST AREA TODAY...WITH
EFFECTIVE SNOW COVER GONE AND BETTER COOL ADVECTION TO OUR
NORTH...BUMPED UP TEMPERATURES A BIT FOR TODAY WITH WARMER MAV
GUIDANCE APPEARING BETTER. WITH INCREASING SERLY SFC FLOW AND
ISENTROPIC LIFT...CLOUDS SHOULD INCREASE LATE TNGT/SAT. ALTHOUGH
PROBABLY NOT YET COMPLETELY CLOUDY AND LOW LVLS STILL PROBABLY TOO
DRY FOR APPRECIABLE PCPN...ALTHOUGH KEPT IN SMALL POPS SOUTH.
MUCH HIGHER PRECIPITATION PROBABILITIES SATURDAY NIGHT INTO SUNDAY AS
UPPER TROUGH INDUCES SFC CYCLOGENESIS OVER NE COLORADO WITH LOW
LIFTING NW OF OMAHA BY 18Z SUNDAY ADVECTING 6-10 DEG C H85 DWPTS
NWD. 00Z ECMWF WAS VERY CLOSE TO 00Z GFS MEAN AND PUTS SERN 1/2 OR
SO OF THE FORECAST AREA IN THE WARM SECTOR AND POSSIBLY REDUCING
THE FREEZING RAIN THREAT OVER OUR AREA AS WELL. ALTHOUGH SOME OF
IT CANNOT BE RULED OUT...MOSTLY FAR NWRN ZONES...EITHER EARLY
SUNDAY OR AFTER COLD AIR RUSHES SEWD AS SYSTEM PASSES. ALSO
DECENT AGREEMENT IN MODELS BRINGING NEGATIVE H85 LIFTED INDICES
OVER CWA AS STEEP MID LVL LAPSE RATES DEVELOP/SPREAD NEWD. THUS AT
LEAST ISOLD TSTM MENTION STILL LOOKS ON TRACK...IN FACT THIS
MENTION WAS SPREAD A BIT FARTHER N AND LINGERED ACROSS E SUNDAY
MORNING. BECAUSE OF EXPECTED SURFACE LOW TRACK PULLED SOME 60
DEGREE TEMPERATURES INTO THE LNK/OMA AREA AND LOCATIONS SOUTHEAST.
WOULD GO WARMER BUT SYSTEM IS PRETTY PROGRESSIVE AND COLD FRONT
COULD CUT THINGS OFF FAIRLY QUICKLY. COULD SEE FAR SERN ZONES
NEEDING A FURTHER BUMP IN LATER FORECAST IF TRENDS PERSIST. ENERGY
IN EJECTING UPPER TROUGH APPARENTLY SPLITS BY MONDAY WITH MAIN
UPPER LOW TO OUR NORTH AND BETTER LOW LEVEL MOISTURE
CONVERGENCE/CONVECTION TO OUR SOUTH. THUS TRIMMED BACK/REMOVED
SOME PRECIPITATION CHANCES SUN NGT/MONDAY ACROSS SECTIONS OF THE
CENTRAL/SRN FORECAST AREA. THIS CURRENT SCENARIO WOULD POINT TO
ANY HEAVY SNOW AND SIGNIFICANT FREEZING RAIN THREAT WILL BE NORTH
OF THE FORECAST AREA.
CERTAINLY ISOLATED HEAVIER POCKETS OF RAIN EARLY SUNDAY WOULD
AGGRAVATE ONGOING ICE JAM/ISOLATED FLOODING PROBLEMS. HOWEVER...IT
CURRENTLY APPEARS AREAL RAIN AMOUNTS WILL BE MODEST BUT SUBJECT
TO CHANGE.
PATTERN COOLS DRAMATICALLY MONDAY AS UPPER LOW CLOSES OFF TO OUR N
THEN OPENS UP EWD...STRONGER AND FARTHER SOUTH THAN SYSTEM THIS
MORNING. SO IT LOOKS LIKE WE MAY ACTUALLY GET THE COOLER AIR THIS
TIME UNLIKE TODAY WHICH SEVERAL DAYS APPEARED WOULD BE MUCH COOLER
THAN IT APPARENTLY WILL BE.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS WILL PREVAIL THRU THE FCST PD. SFC HIGH PRESSURE WILL
PASS OVER THE REGION KEEPING SFC WINDS LIGHT.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/KERN