FXUS63 KOAX 252208
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
408 PM CST FRI FEB 25 2011
.SHORT TERM...TONIGHT THROUGH MONDAY.
GIVEN CURRENT 88D MOSAIC LOOP...12Z NAM APPEARS TO HAVE BEST HANDLE
ON NARROW LINE OF LIGHT SNOW OVER SC/SE NEB WITH ACTIVITY MATCHING UP
PRETTY WELL WITH DENDRITIC OMEGA AXIS. LATEST RUC13 AND HRRR LENDING
CREDENCE TO THE NAM SOUTHERLY SNOWFALL TRACK THRU THIS EVENING...THUS
WILL FOCUS POPS MAINLY ALONG I-80 CORRIDOR. AFTER MIDNIGHT AND
INTO SAT AFTN EXPECT LARGER AREAL COVERAGE OF LIGHT SNOW WITH ONSET
OF STOUT 295K UPGLIDE. HOWEVER DO NOT THINK AMOUNTS WILL BE MUSH MORE
THAN 1 TO 2 INCHES IN GENERAL GIVEN UPPER DYNAMIC SUPPORT NOT IN
FULL FORCE OVER THE CWA. FOR SAT NIGHT...BUFKIT SOUNDINGS
CONTINUE TO SUPPORT GOING FCST OF -FZDL.
VASTLY MORE POTENT VORT LOBE ENTERS THE CNTRL PLAINS SUNDAY EVENING
WITH 500MB HFC TRACKING RIGHT ACROSS KS/OK WITH ASSOCIATED DPVA
EVENTUALLY INDUCING CYCLOGENESIS IN WRN KS. SFC PATTERN BECOMES MORE
FAVORABLE THEN FOR GOOD GULF MOIST RETURN TO TAP INTO AND PHASE
WITH STRONG SYNOPTIC SCALE FORCING IS. HOWEVER MAIN CONCERN WITH
THIS SYSTEM IS PCPN TYPE. SFC LOW EXITS KS INTO MO LATE SUNDAY
NIGHT AND SHOULD BEGIN THE PROCESS OF PCPN CHANGE OVER FROM RAIN/-
FZRA/SLEET/SNOW OVER THE CWA...MORE SPECIFICALLY BTWN 06Z-12Z MON.
PER CRITICAL THKNS/BUFKIT SOUNDINGS. GIVEN SPEED NATURE OF THE
SYSTEM...BEST FORCING/MOISTURE SHOULD BE WELL EAST OF THE AREA WHEN
BRUNT OF CAA FILTERS INTO THE CNTRL PLAINS. HOWEVER...THINKS
SOUTHEAST SECTIONS WILL RECEIVE SOME SNOW ACCUMULATIONS BEFORE THE
SYSTEM COMPLETELY PULLS OUT.
DEE
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
WEATHER APPEARS MAINLY QUIET IN THE EXTENDED AS WEAK UPPER-LEVEL
RIDGING CONTINUES THROUGH MIDWEEK...WITH A TRANSITION TO
SOUTHWESTERLY FLOW BY AROUND THURSDAY AS AN UPPER-LEVEL TROUGH
BECOMES POISED TO MOVE ACROSS THE CENTRAL PLAINS FRIDAY-SATURDAY.
RETURN FLOW IS PROGGED TO DEVELOP MONDAY NIGHT AND TUESDAY AS
SURFACE RIDGING MOVES EASTWARD...AND HAVE BUMPED UP TEMPS IN BOTH OF
THOSE PERIODS WITH SOUTH TO SOUTHWEST FLOW ACROSS THE AREA.
SHORTWAVE SOMETIME LATE TUESDAY INTO WEDNESDAY WILL PROVIDE A
REINFORCING SHOT OF COLDER MID-LEVEL TEMPS TO THE AREA...THOUGH
FRONTAL PASSAGE LOOKS DRY. KEPT TEMPS ON WEDNESDAY NEAR
CLIMO...THOUGH BY WEDNESDAY NIGHT...SOUTHERLY TO SOUTHEASTERLY
COMPONENT TO LOW-LEVEL FLOW RETURNS. WARM AIR ADVECTION LOOKS
PARTICULARLY STRONG ON THURSDAY AS A SHORTWAVE MOVES FROM THE
NORTHERN PLAINS TO THE GREAT LAKES...AND HAVE NUDGED TEMPS UPWARD
THERE.
BOTH ECMWF/GFS DEVELOP A DEEPENING UPPER LOW IN THE SOUTHERN PLAINS
SOMETIME AROUND FRIDAY...WITH THE LOW BOWLING ACROSS THE SOUTH INTO
SATURDAY. 00Z ECMWF WAS MUCH DEEPER THAN 12Z GFS...BUT OVERALL
PATTERN IS CONSISTENT. FOR NOW...HAVE NOT ADDED POPS...AS MODELS
INDICATE QUITE A RANGE OF UNCERTAINTY FOR DEPTH OF THE
LOW...TIMING...AND POSITION...BUT WILL NEED TO MONITOR THE SYSTEM AS
IT APPROACHES.
MAYES
&&
.AVIATION...
18Z TAFS
COLD HIGH PRESSURE AT THE SURFACE WILL SHIFT TO THE EAST THRU
SATURDAY WITH NORTH SFC WINDS AT 5 TO 10 KTS WILL BECOME EAST AND
SOUTHEAST AFTER 12Z SATURDAY. A WEAK SHORTWAVE TROF WILL AFFECT THE
TAF SITES INTO TONIGHT WITH PERIODS OF MVFR CIGS AND LIGHT SNOW AND
PATCHY MVFR VSBYS. THE FORECASTED MOISTURE PROFILES HOLD ONTO THE
MOISTURE INTO SATURDAY...THUS HOLD ONTO THE MVFR/VFR CIGS THRU THE
PD.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$