FXUS63 KOAX 140924
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
324 AM CST FRI JAN 14 2011
.DISCUSSION...
FORECAST IS NOT VERY CLEAR CUT IN THE FIRST 3-4 DAYS AS FORECAST
AREA REMAINS IN NWRLY FLOW ALOFT WITH A SERIES OF WEAK WAVES
BRINGING RELATIVELY SMALL PCPN CHCS. THERMAL FIELDS ALSO TRICKY AS
WARM WEDGE OF AIR ALOFT TDA GETS SHOVED SSW OF CWA ON SATURDAY BUT
RETURNS LATE SUN/SUN NGT...THUS PCPN TYPE ALSO IN QUESTION.
MORNING STLT IMAGERY SHOWED FIRST WAVE MOVG THRU WY SPREADING MID
CLOUDS SE TWD ERN NEBR AS OF 09Z. PCPN...GENERALLY
ALOFT...INDICATED BY KLNX RADAR WAS NOT TOO FAR OFF FM WHERE 00Z
GFS WAS PAINTING LGT MORNING QPF. DECENT ISENTROPIC UPGLIDE
FCST THIS MORNING INTO THIS AFTN NEAR 290K SFC BY GFS/NAM
CONCENTRATING ON NERN ZONES WHERE CONDENSATION PRES DEFICITS WERE
LOWEST. THUS KEPT IN SLGT CHC POPS NERN ZONES TDA AND WL COUNT ON
DRY AIR IN H8-H9 LYR KEEPING EVERYTHING ALOFT FARTHER S. WARM
WEDGE COULD BE WARM ENOUGH SO THAT IF PCPN FALLS IT WOULD BE ZR
INSTEAD OF SLEET...BUT WITH SUCH COLD TEMPS NEAR SFC ATTM LEFT
SLEET IN FCST N. SFC TEMPS SHOULD MODERATE AS A WEAKENING SFC
REFLECTION OF UPPER WAVE PASSES EAST...BUT KEPT THEM IN MID 20S
NERN ZONES ATTM. THIS WAVE WILL PULL DOWN SOME MODIFIED ARCTIC
AIR LATE TNGT/SAT WITH TEMPS PROBABLY STEADY/FALLING ON SAT.
HOWEVER...COLDER AIR DOESN/T ARRIVE UNTIL LATE TNGT THUS RAISED
LOWS A BIT..SPCLY S. LEFT IN SMALL SNOW CHCS POST FRONTAL NWRN
ZONES AND INCLUDED FLURRIES A BIT FTHR SE SAT AM. THERE WAS STILL A
WIDE RANGE BETWEEN MAV/MET FOR LOWS SAT NGT AND A LOT WL DEPEND
ON HOW MUCH CLEARING OCCURS...IF ANY...SAT EVENING BEFORE WARM
ADVCTN BEGINS AGAIN LATE. ATTM MADE LTL/NO CHANGES TO LOWS WHICH
WERE CLOSE TO A COMPROMISE.
A WEAK WAVE SAT NGT/SUN COULD SPREAD MORE PCPN ACROSS CWA WHICH
WAS HIT ESPECIALLY HARD BY 00Z NAM. THAT MODEL WAS MORE OF AN
OUTLIER FM GFS/ECMWF...AND 06Z VERSION DID SHIFT MORE TWD 00Z
ECMWF SOLUTION. PCPN TYPE...IF ANY...IS INDICATED AS A PD OF SNOW
BUT BEFORE LIFT BEGINS AND AFT IT ENDS MOISTURE IN DENDRITIC LAYER
DRIES OUT THUS FZDZ COULD OCCUR AND MENTIONED SOME SRN ZONES.
KEPT TEMPS CLOSER TO PREV FCST/GFS MAV ON SUN.
STRONGER WAVE SUN NGT/MON...SPCLY PER 00Z ECMWF/GFS...SHOULD BRING
HIGHER POPS TO THE CWA AFT 06Z MON ALONG WITH STEADY/RISING TEMPS
INTO MON MORNING BEFORE FALLING AGAIN BEHIND A STRONGER COLD PUSH.
ADJUSTED MIN AND MAX TEMPS UPWARD SUN NGT/MON RESPECTIVELY AND
ALSO INCLUDED FREEZING RAIN MENTION AS A VERY WARM WEDGE NEAR H85
PUSHES INTO SERN NEBR BY 12Z....+4 TO +6 PER ECM/GFS. SFC TEMPS
COULD ATTEMPT TO CLIMB TO FREEZING BEFORE PCPN ARRIVES S...BUT
SEEMS QUESTIONABLE ATTM MOST AREAS AND JUST LIMITED 32 TO FAR SRN
NEBR ZONES MON AM WITH FALLING TEMPS BY AFTN.
NO CHANGES TO EXTENDED. TURNING COLDER AGAIN THRU MIDWEEK BEFORE
ADDITIONAL WAVES LATE NEXT WEEK/NEXT WEEKEND POSSIBLY PROVIDE A
REPEAT TO WHAT WILL BE HAPPENING THIS WEEKEND.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
VFR CONDITIONS ARE EXPECTED THRU MUCH OF THE PD. A FEW ECHOES MAY
SHOW UP ON RADAR LATE THIS MORNING THRU THE AFTN HOWEVER WE DO NOT
EXPECT MUCH PCPN TO HIT THE GROUND AS IT EVAPORATES IN A DRY LAYER
JUST ABOVE THE SFC. A WEAK SFC TROF WL MOVE OVER THE SITES AND HIGH
PRESSURE WL BEGIN TO MOVE IN LATE IN THE PERIOD WHICH WL CREATE A
GRADUAL WIND SHIFT TO THE NORTHWEST VERY LATE IN THE PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
CHERMOK/KERN