FXUS63 KOAX 272117
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
317 PM CST SUN FEB 27 2011
.SHORT TERM...TONIGHT THROUGH WEDNESDAY.
MAIN ISSUE CONTINUES TO BE PCPN/PCPN TYPE RELATED TO POTENT SHORTWAVE
TROF CROSSING THE CNTRL PLAINS TONIGHT. MODELS STILL QUITE CLEAR
FOCUSING BEST CHANCES OVER THE SRN CWA ALONG SW-NE ORIENTED
AGEOSTROPHIC FORCING ASSOCIATED WITH LOW/MID LEVEL QG FRONTOGENESIS.
QUESTION AS TO AMOUNT OF LLVL MOIST TO TAP INTO DEPENDENT UPON SPEED
OF SFC LOW TRACKING EWD THRU KS. COMPARED TO LAST COUPLE RUNS THIS
MORNING 12Z NAM JACKED UP QPF AMOUNTS PENETRATING THE CWA TONIGHT.
HOWEVER...18Z NAM HAS JUST ARRIVED AND HAS BACKED OFF QPF AMOUNTS
SIGNIFICANTLY. AM INCLINED AT THIS POINT TO LEND SOME CREDENCE TO 18Z
NAM SOLUTION GIVEN LATEST RUC13 AND HRRR TRENDING THE SAME WAY. THUS
WILL BACK OFF OVERNIGHT POPS JUST A BIT FOR AREAS SOUTH OF I-80. AT
ANY RATE PCPN TYPE WILL BE AN ISSUE WITH ANY ACTIVITY THAT DEVELOPS
AND STILL EXPECT A MIX OF LIQUID/FREEZING/FROZEN. HAVE ACTIVITY
SHUTTING OFF BY 12Z MON AS ALL MODELS DEPICT BEST MOIST/LIFT EAST OF
THE AREA BY THEN. OTHERWISE...WILL CONTINUE DRY FCST MON THRU WED.
DEE
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THE LARGE-SCALE PATTERN
THROUGH THE EXTENDED TODAY. MOST MODELS...SHOW A SHRTWV TROF /WITH
VARYING SPEEDS OF MOVEMENT/ ALLOWING FOR THE DEVELOPMENT OF A CNTRL
AND ERN US TROF LATE IN THE WEEK AND INTO NEXT WEEKEND. THURS
SHOULD BE THE NICEST OF THE DAYS IN THE EXTENDED WITH THE CWA AHEAD
OF THE SFC CDFNT. MOISTURE WILL INCREASE ON THURS...BUT MUCH OF THE
DYNAMICS ASSOCIATED WITH THE LEAD SHRTWV WILL GO NORTH AND E OF THE
FA. NEVERTHELESS THERE IS SOME INDICATION OF LARGE-SCALE
FORCING/ISENTROPIC LIFT AND WILL LEAVE IN THE LOW CHC POPS FOR SOME
SHOWERS. SFC CDFNT THE MOVES THRU THE FA ON THURS NIGHT WITH COOLER
AIR SPILLING INTO THE FA FOR FRI AND THE WEEKEND. NO REAL ARCTIC AIR
IN STORE FOR THE AREA...BUT NEAR OR SLIGHTLY BELOW NORMAL APPEARS
LIKELY.
THE MAIN DIFFERENCE IN THE EXTENDED IS HOW MUCH ENERGY WILL END UP
IN THE SRN END OF THE TROF AS IT SWINGS THRU THE CNTRL PLAINS NEXT
FRI INTO SAT. SOME OF THE ENSEMBLES INDC THAT THERE MAY BE ENOUGH
FORCING TO GENERATE SOME LIGHT PRECIP DURING THIS TIME. GIVEN THE
UNCERTAINTY IN THIS PATTERN HAVE POPS CURRENTLY ENDING ON THURS
NIGHT AND WILL LEAVE FRI/FRI NIGHT DRY ATTM. THE GFS THEN SEEMS TO
AGGRESSIVE IN THE RETURN FLOW LATER IN THE WEEKEND AND THE EC
APPEARS TO COLD AND WET...AND THUS TRENDED THE FORECAST TOWARD THE
ENSEMBLE MEAN DURING THE WEEKEND.
JB
&&
.AVIATION...
18Z TAFS
MVFR CEILINGS ARE EXPECTED AT KOMA/KLNK THROUGH 28/07-08Z. THE
CEILING AT KOFK HAD SCATTERED OUT...BUT COULD BUILD BACK TO THE WEST
LATE THIS AFTERNOON OR EARLY EVENING AS WELL. OPTED TO KEEP
PRECIPITATION OUT OF THE TAF SITES. WHILE THERE WILL BE PRECIP IN
THE COUNTY WARNING AREA...FELT CONFIDENT THAT IT WOULD REMAIN JUST
SOUTHEAST OF KLNK AND KOMA AT THIS TIME.
&&
WALDO
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$