FXUS63 KOAX 050928
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
328 AM CST SAT DEC 5 2009
.DISCUSSION...
SYNOPSIS...00Z UPPR AIR ANLYS INDCD SHRTWV RIDGE FM THE HIGH
PLAINS TO THE 4 CORNERS AREA. THE FIRST OF OUR SIG WX MAKERS FOR
THE NEXT FEW DAYS WAS MOVG THRU THE PAC NW ASSOCIATED WITH A 210 M
H5 HEIGHT FALL AT KOTX AND A 100 KT H3 JET. 08Z SFC ANLYS INDCD
RIDGE AXIS EXTNDD FM IL INTO THE SRN PLAINS. LO PRES WAS DVLP OVR
THE ERN PLAINS OF WY AND CO.
FORECAST...QUIET DAY IN STORE FOR THE FA AS UPSTRM SHRTWV RIDGE
MOVES OVER. SHLD SEE PLENTY OF SUN...BUT DID COOL HIGHS A TOUCH
TODAY CLOSER TO THE COOLER MET PER RECENT MOS VERIFICATION AND
EXPECTED MIXING TO H9. DVLPNG SFC CDFNT FM NW MN INTO WRN SD WL
BE ON THE MOV S TODAY. MODELS ARE IN GOOD AGREEMENT IN THE
MOVEMENT OF THE FNT AND SHLD BE NEAR I-80 BY 00Z. UPPR LVL SHRWV
TROF OVR THE PAC NW WL START TO HEAD EWD TONIGHT...AND AS THE
UPPR LVL FLOW BECOMES INCREASINGLY ZONAL OVERNIGHT...SHLD SEE THE
CLDS INCREASE. LIFT WL INCREASE DURING THE DAY ON SUN AS UPPR LVL
TROF MOVS TOWARD THE HIGH PLAINS. AS PRES ADVECTION INCREASES ON
THE 1.5 PVU SFC...A DECENT FRONTAL CIRCULATION DVLPS. EXACTLY
WHERE THE FRONTAL BAND DVLPS IS STILL SOME QUESTION AS THE NAM IS
FARTHER THAN THE MOST GUIDANCE...AND A COMPROMISE OF THE
GF/EC/CANADIAN WAS USED FOR PLACEMENT OF THE BAND. CROSS SECTIONS
INDC THE ATMOSPHERE IS FAIRLY STABLE ABOVE THE FRONT FOR THE
EVENT WITH EPV ABOVE 1 IN MOST CASES. THUS PRECIP INTENSITY SHLD
NOT GET OUT OF HAND AND CSI IS NOT EXPECTED WITH THIS SYSTEM.
INCREASED POPS THRU THE AFTN AND INTO THE EVENING HOURS WHEN BEST
LIFT IS PROGGED. LITTLE INFLUENCE FM THE GULF IS EXPECTED WITH
THIS SYSTEM WITH THE SFC RIDGE OVR THAT AREA NOW THRU TONIGHT.
SYSTEM IS ALSO FAIRLY FAST...AND THESE TWO FACTORS WL TEND TO HOLD
DOWN AMOUNTS. IN ADDITION...LO LVL RH IS PRETTY MEAGER AND WITH
THE BEST LIFT ABOVE THE DENDRITIC ZONE /MAINLY IN THE NRN
CWA/...SNOWFLAKES MAY NOT BE THE BEST AT ACCUMULATING. WILL GO
WITH A STRIPE OF 2 TO 4 INCHES JUST NORTH OF THE I-80 CORRIDOR FOR
THE EVENT WITH AMOUNTS TAPERING PRETTY QUICKLY ON BOTH SIDES.
PRECIP SHLD GENERALLY BE DONE AFTER MIDNIGHT BUT CLD SEE SOME
MINOR BLOWING AND DRIFTING GIVEN THE 15 TO 20 MPH WINDS SUN NIGHT.
THE COMBINATION OF CAA...LIMITED SUN AND EXPECTED FRESH SNOW COVER
LED TO THE LOWERING OF HIGHS ON MON AND WE MAY NOT GET OUT OF THE
TEENS FOR MAXES. NEXT SYSTEM WILL QUICKLY START TO IMPACT THE AREA
ON MON NIGHT AS WAA INCREASES THRU THE NIGHT. MOST MODELS APPEAR
CONSISTENT IN DVLPG SOME -SN DURING THIS TIME FRAME AND HAVE
INCREASED POPS FARTHER N TO THE SD BORDER. OTHERWISE LITTLE CHANGE
FM THE PREVIOUS FORECAST FOR THE TUES/TUES NIGHT TIME FRAME.
MODELS STILL DIFFER ON THE EVENTUAL TRACK OF THE SHRTWV...BUT DOES
LOOK LIKE AT LEAST SOME SN FOR THE AREA. SYSTEM IS ONCE AGAIN
PRETTY FAST AND DOES NOT CLOSE OFF A MID LVL CIRCULATION /LIMITING
ANY POTENTIAL TROWAL/ SO THIS MAY HOLD DOWN AMOUNTS. DID INCREASE
WINDS FOR TUES NIGHT AND ADDED SOME BLOWING SNOW WORDING. ONLY
OTHER CHANGE TO THE FORECAST PAST WED WAS TO MAKE PRECIP TYPE ALL
SN FOR THURS NIGHT...WHICH MATCHES BETTER CURRENT TMP FORECAST.
BOUSTEAD
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDS WILL PREVAIL ACROSS ALL THREE TAF SITES THROUGH THE
REMAINDER OF THE FORECAST PERIOD WITH SOUTHERLY WNDS SHIFTING
TO THE NORTHWEST AFTER 05/18Z...ACROSS ALL THREE TAF SITES AND
THE REST OF THE STATE BY THE END OF THE FORECAST PERIOD. EXPECT
NORTH WINDS ACROSS ALL THREE TAF SITES BY 06/00Z.
REESE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
