FXUS63 KOAX 042117
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
317 PM CST FRI MAR 4 2011
.SHORT TERM...TONIGHT THROUGH MONDAY.
PCPN ACTIVITY OVER SRN CWA/NERN KS/NW MO IN ASSOCIATION WITH LOW/MID
LYR AGEO LIFT AS SIGNIFICANT CAA PLUNGES SWD INTO THE CNTRL PLAINS.
AS A MATTER OF FACT...TEMPS OVER THE WRN DAKOTAS/ERN MT HAD DROPPED
INTO THE SINGLE DIGITS AS OF 20Z OBS. FOR THIS FCST PACKAGE HAVE
DECIDED TO LEAN TOWARD GFS/CMC SOLUTIONS WHICH HAS GOOD SUPPORT FROM
THE UKMET/SREF THRU 84 HRS. FOR TONIGHT PAIR OF VORTS CROSS THE
CNTRL/SRN PLAINS RESPECTIVELY WITH UPPER LVL LONGWAVE TROF. EXPECT
ACTIVITY TO THE SOUTH WILL COME TO AND END SOMETIME THIS EVENING WHEN
SUBSIDENCE FILLS IN BEHIND EXITING SRN ENERGY. MEANWHILE NIL
PCPN DEVELOPMENT ANTICIPATED OVER CWA FROM NRN PLAINS VORT ENERGY
GIVEN LACK OF MOISTURE. ON SATURDAY UPPER TROF AXIS SHIFTS WELL EAST
OF THE REGION AND ALLOWS NARROW WEDGE OF CANADIAN SFC HIGH PRESS TO
BUILD SWD THRU THE GREAT PLAINS. LARGE SCALE PATTERN UPSTREAM
SATURDAY AFTN BEGINS TO TRANSITION TO NEAR ZONAL WITH SEVERAL
EMBEDDED IMPULSES RIDING THRU THE FLOW. MODELS FOCUS IN ON ONE IN
PARTICULAR PASSING IN THE VICINITY OF THE NRN CWA SAT NIGHT/SUN NIGHT
TIME FRAME. FOCUS FOR SNOW DEVELOPMENT MAINLY OVER SD/MN WHERE BEST
MOISTURE IS TO BE FOUND. HOWEVER STILL REASONABLE TO CONTINUE SMALL
POPS UP NORTH AT THAT TIME. AS MENTIONED...LATEST RUN OF
CMC/UKMET/GFS/SREF IN REMARKABLY GOOD AGREEMENT LEADING INTO NEXT
WEEK WITH RESPECT TO TIMING/PLACEMENT OF UPSTREAM TROF AS WELL AS
ASSOCIATED SFC FEATURES IN THE PLAINS. WRN TROF DIGS DOWN THE WRN
CONUS THEN INTENSIFIES WHEN IT MOVES OVER THE GREAT BASIN REGION LATE
MONDAY AFTN. MEANWHILE CHANCE FOR PCPN MIX OVER NRN/CNTRL PLAINS
MONDAY MORE RELATED TO STRONG ISENTROPIC UPGLIDE/MOIST ADVECTION
ALONG 295K PRESSURE SFC. FOR NOW HAVE -SN POPS ENTIRE CWA DURING THE
MORNING..THEN RA/SN MIX NORTH AND RA SOUTH. QPF PROGS GENERALLY
ADVERTISING LIQUID AMOUNTS AROUND A HALF INCH ALONG THE SD/NEB
BORDER. DIFFICULT TO DETERMINE EXACTLY HOW FAR SOUTH CAA WILL
PENETRATE THE CNTRL PLAINS...SO SITUATION DEFINITELY BEARS CLOSE
WATCHING.
DEE
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY.
MESSY FORECAST PERIOD TO SAY THE LEAST WITH POTENTIAL WINTER STORM
IN ADDITION TO THUNDERSTORMS.
PERIOD BEGINS WITH UPPER TROF DIGGING ACROSS THE FOUR CORNERS REGION
AND QUICKLY CLOSES OFF AND MOVES INTO THE CNTRL PLAINS REGION BY TUE
NIGHT. SOME VARIABILITY REMAINS WITH THE TIMING OF THE LOW BUT ALL
MODELS POINT TO A HEAVY SNOWFALL ACROSS PORTIONS OF THE CWA TUESDAY
INTO WEDNESDAY. EXACTLY WHERE THE RAIN/SNOW LINE WILL END UP IS THE
MILLION DOLLAR QUESTION AT THIS POINT. AFWA ENSEMBLE PRODUCTS
CONTINUE TO SHOW GOOD PROBABILITY OF 6" OR GREATER SNOWFALL OVER A
GOOD CHUNK OF OUR NORTHERN CWA AND THIS IS ON TRACK WITH BOTH 12Z
ECMWF AND GFS AS A DEFORMATION BAND FORMS ON THE BACKSIDE OF THE
SYSTEM OVERNIGHT TUESDAY INTO WEDNESDAY. A FEW THINGS LOOK FOR
CERTAIN WITH THIS SYSTEM. THE FIRST IS THAT THERE WILL BE COPIOUS
AMOUNTS OF MOISTURE LEADING TO HIGH PRECIPITATION AMOUNTS WHETHER IT
BE RAIN OR SNOW OR A MIX. THE SECOND IS THAT THERE WILL BE A TIGHT
SNOWFALL VS RAIN GRADIENT SOMEWHERE IN OUR FORECAST AREA ALONG WITH
THE POTENTIAL FOR THUNDERSTORMS IN THE WARM SECTOR. THE THIRD IS
THAT THERE WILL BE A STRONG SFC GRADIENT AS WE GET ON THE BACK SIDE
OF THE LOW WHICH SHOULD BRING SFC WINDS UP TO 30KTS OR MORE.
KERN
&&
.AVIATION...
18Z TAFS
KEPT MVFR CONDITIONS AT BOTH KOMA/KLNK THROUGH THE PERIOD...MAINLY
FOR CEILINGS...ALTHOUGH VISIBILITIES COULD STILL BE IN THE 5 MILE
RANGE AT KOMA THROUGH ABOUT 22Z. ALSO EXPECTING MVFR CEILINGS TO
RETURN TO KOFK THROUGH THE AFTERNOON AND CONTINUE OVERNIGHT AS WELL.
CEILINGS SHOULD BEGIN TO SCATTER OUT BY 05/12-14Z. REGARDING
PRECIPITATION...FEEL THAT ANY SHOWERS WILL BE SOUTHEAST OF KLNK/KOMA
LATE THIS AFTERNOON AND EARLY EVENING...THUS LEFT THEM OUT. SOME
SPOTTY FLURRIES IN NORTH CENTRAL NEBRASKA COULD MAKE A PUSH EASTWARD
TOWARD KOFK...BUT LATEST MODEL SOLUTIONS SUGGEST THEY SHOULD FIZZLE
OUT.
WALDO
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$