Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 211746
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1246 PM CDT MON APR 21 2014

.UPDATE...
ISSUED AT 1242 PM CDT MON APR 21 2014

PRECIPITATION EXITED SOUTHEAST NEBRASKA AND SOUTHWEST IOWA SHORTLY
AFTER NOON TODAY. POTENT PRESSURE RISES BEHIND THE FRONT/PRECIP
WAS CAUSING GUSTY NORTH WINDS ACROSS ALL OF OUT AREA. DEEP MIXING
WAS ALSO CONTRIBUTING TO DRYING OF LOW LEVELS...AND DEW POINTS
WERE DROPPING WELL INTO THE 20S. AND WITH TEMPERATURES IN THE LOW
TO MID 70S...RELATIVE HUMIDITY VALUES ARE EXPECTED TO DROP BELOW
20 PERCENT FOR A GOOD PART OF NORTHEAST NEBRASKA. THUS HAVE
EXPANDED OUR RED FLAG WARNING TO INCLUDE A FEW MORE
COUNTIES...ESPECIALLY THOSE THAT DID NOT SEE MUCH RAIN
YESTERDAY/THIS MORNING. STILL HAVE QUITE A BIT OF DRY FUELS.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 300 AM CDT MON APR 21 2014

OTHER THAN LINGERING CONVECTION THIS MORNING MAIN FOCUS IN SHORT
TERM WILL BE WEDNESDAY AS A STRONG UPPER TROUGH/LOW TAKES SHAPE
NEAR CANADIAN/MT BORDER BY MIDWEEK.

FOR TODAY...SCATTERED CONVECTION CONTINUES TO BUBBLE ACROSS
FORECAST AREA AHEAD OF A COLD FRONT THAT WAS NEAR AN ONEILL TO ORD
LINE AT 08Z. SHORT TERM 4KM WRF/HRRR/RAP TAKE IT EAST OF FA BY
18-19Z AND APPEARS FRONT WILL HAVE A DRY ENOUGH PUSH TO IT SO THAT
IF REDEVELOPMENT OCCURS WITH HEATING IT WILL BE SE OF AREA. GIVEN
UPSTREAM DWPTS AND GOOD MIXING EXPECTED THIS AFTERNOON...APPEARS
AT LEAST NRN ZONES WILL REACH EXTREME FIRE DANGER READINGS THIS
AFTERNOON AS RH VALUES DROP TO NEAR 20 PERCENT AND GUSTY NORTH
WINDS PERSIST. A RED FLAG WARNING WILL BE ISSUED ACROSS THE N. IF
ANYTHING IT MAY HAVE BE EXPANDED THIS MORNING IF NAM DRYING COMES
TO FRUITION FARTHER SE. LITTLE CHANGES TO PREV TEMPS WITH MIXING
EXPECTED TO BOOST MOST READINGS AT LEAST INTO LOWER 70S TDA.

DRY WEATHER THEN FOR TONIGHT/TUESDAY AND PROBABLY TUESDAY EVENING
AS SFC RIDGE BUILDS DOWN MO RIVER BEFORE SHIFTING EWD. WITH DRY
AIRMASS IN PLACE TONIGHT AND A VERY SLOW RECOVERY...IF
ANY...ON TUESDAY...LOWERED LOWS TONIGHT AND DWPTS A BIT ON
TUESDAY. ALTHOUGH NO CHANGES WERE MADE TO MAX TEMPS TUESDAY...THE
LOWER DWPTS COULD AGAIN BRING INCREASED FIRE DANGER CONDITIONS IF
DWPTS WOULD LOWER A LITTLE MORE AND WINDS INCREASE A BIT QUICKER
ON TUESDAY. THE DRY AIR COULD ALSO LIMIT COVERAGE OF WARM
ADVECTION SHOWERS/TSTMS LATE TUE NIGHT INTO WEDNESDAY...BUT KEPT
HIGH END CHANCE POPS MOST AREAS IN FORECAST FOR NOW. GFS/ECMWF
CONTINUE TO SUGGEST SYNOPTIC WARM FRONT COULD LIFT MOSTLY N THRU E
OF FCST AREA WED WHILE NAM KEPT IT MOSTLY TO THE WEST/SOUTH.
SINCE THE ECMWF HAS BEEN A LITTLE INCONSISTENT IN THIS REGARD AND
NAM KEPT US MOSTLY ON THE COOLER SIDE...LEFT MAX TEMPS PRETTY MUCH
ALONE WHICH WERE CLOSE TO A BLEND BETWEEN COOLER MET AND WARMER
MAV. RESIDUAL CLOUDS/PRECIP AND FRONTAL LOCATION AMONG MOVING
PARTS IMPACTING POTENTIAL CONVECTIVE EVOLUTION WED AFTN/EVENING AS
WELL AS MOISTURE RETURN WHICH COULD ALSO IMPACT COVERAGE OF SEVERE
STORMS. HOWEVER...DYNAMICS FROM SYSTEM ALONE APPEAR TO BE STRONG
ENOUGH TO KEEP CATEGORICAL POPS IN MOST AREAS WED NIGHT...ALTHOUGH
COULD SEE TIMING OF HIGHEST POPS BE MOVED UP TO LATE AFTN PARTS OF
WEST.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 300 AM CDT MON APR 21 2014

SOME INDICATIONS THAT A LEAD LOBE...IF NOT ENTIRE TROUGH/LOW AXIS
ITSELF...WILL SHIFT EAST OF THE AREA BY THURSDAY. IF SO POPS MAY
SHIFT EAST OF AREA AS WELL. IF ENOUGH ENERGY/MOISTURE REMAINS
FARTHER WEST COULD SEE ISOLD CONVECTION DEVELOP WITH HEATING AGAIN
THURSDAY DESPITE DOWNSLOPE WINDS AS COLD H5 THERMAL TROUGH PIVOTS
OVER AREA AND MODERATE LAPSE RATES DEVELOP AS LOW LVL COLD
ADVECTION NOT THAT STRONG YET. FOR NOW SPLIT DIFFERENCE LEAVING
POPS IN ERN FA AND KEPT W DRY.

AFTER A PROBABLE DRY FRIDAY...WHETHER PATTERN CAN REMAIN
PROGRESSIVE PER 00Z ECMWF OR ATTEMPT AT LEAST A SHORT TERM BLOCK
PER 00Z GFS SEEMED LIKE A TOSS-UP. THUS KEPT IN MODEL BLEND OF
INCREASING POPS NEXT WEEKEND WITH NO CHANGES TO BLENDED TEMPS.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1242 PM CDT MON APR 21 2014

VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY MORNING. GUSTY NORTH
WINDS 20 TO 30KT WILL CONTINUE THROUGH 00Z BEFORE DIMINISHING TO
LESS THAN 10KT BETWEEN 00Z AND 03Z. OTHERWISE MOSTLY CLEAR SKIES
ARE FORECAST.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR NEZ011-012-
     015>018-030>034-042>045-050-051.

IA...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR IAZ043.

&&

$$

UPDATE...DERGAN
SHORT TERM...CHERMOK
LONG TERM...CHERMOK
AVIATION...DERGAN



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