Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 062335
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
635 PM CDT FRI MAY 6 2016

.SHORT TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 328 PM CDT FRI MAY 6 2016

MAIN FORECAST CONCERNS THOROUGH THE SHORT TERM IS CONVECTIVE
CHANCES INTO EARLY NEXT WEEK.

EARLY AFTERNOON WATER VAPOR IMAGERY INDICATES THE LARGE UPPER-
LEVEL STORM SYSTEM THAT WILL BE THE PRIMARY WEATHER MAKER FOR US
THROUGH MONDAY IS LOCATED OVER THE 4-CORNERS REGION OF THE
SOUTHWEST. ANOTHER SHORT-WAVE TROUGH OF INTEREST WAS MOVING
THROUGH THE SOUTHERN CANADIAN PRAIRIES. SURFACE COLD FRONT
ATTENDANT TO THIS SYSTEM WAS CURRENTLY ADVANCING SOUTHEAST ACROSS
NORTHERN MN AND INTO SOUTHERN SD. THREE-HOUR PRESSURE FALLS OF
2-3 MB BEHIND THE COLD FRONT SHOULD ALLOW THIS TO CONTINUE TO
ADVANCE SOUTHEAST INTO OUR CWA OVERNIGHT. MOISTURE AHEAD OF THIS
FRONT IS VERY MEAGER WITH AFTERNOON DEW POINTS IN THE LOWER TO MID
40S. NEVERTHELESS DEEP MIXING ALONG AND BEHIND THE BOUNDARY THIS
AFTERNOON OVER THE DAKOTAS MAY ALLOW FOR ISO TO SCT SHRA TO
DEVELOP...AND SOME OF THESE MAY SKIRT INTO OUR NORTHERN CWA AFTER
06Z. MODELS ALSO INDICATE A LOW-LEVEL JET STRENGTHENING FROM OK/KS
OVERNIGHT ALLOWING FOR MASS CONVERGENCE OVER OUR SOUTHERN FA
TOWARD MORNING. THUS WILL EXTEND THE SCHC POPS INTO SOUTHWEST IA
AND FAR SOUTHEAST NEB TOWARD 12Z SAT. LITTLE IN THE WAY OF LARGE-
SCALE FORCING FOR ASCENT IS EXPECTED ON SATURDAY WITH THE UPPER-
LEVEL LOW WELL OFF TO OUR WEST AND GENERALLY NEUTRAL TO WEAK
HEIGHT RISES AT H5 THROUGH THE DAY. THIS ALONG WITH THE
SUBSTANDARD MOISTURE RETURN FROM THE GULF OF MEXICO WILL LIKELY
LEAD TO A DRY DAY AFTER THE MORNING ISOLATED SHOWERS SHIFT
EASTWARD.

THUNDERSTORMS ARE EXPECTED TO DEVELOP SATURDAY AFTERNOON OVER THE
HIGHER TERRAIN OF NORTHEAST COLORADO AND NORTHWEST KANSAS. SOME OF
THIS ACTIVITY WILL TRY TO MOVE EAST ON SATURDAY NIGHT...BUT
MOISTURE AHEAD OF THIS ACTIVITY IS REALLY POOR AND THUS
SIGNIFICANT WEAKENING SHOULD OCCUR AS ACTIVITY TRIES TO MOVE INTO
EASTERN NEB AND WESTERN IA. THE BROAD WARM AIR
ADVECTION/ISENTROPIC LIFT AHEAD OF THIS ACTIVITY MAY ALSO LEAD TO
A FEW SHOWERS ON SATURDAY NIGHT. A BIT BETTER CHANCE OF
THUNDERSTORMS WILL FINALLY ENTER THE AREA ON SUNDAY EVENING. THE
UPPER LEVEL LOW WILL START TO TRANSITION TO THE HIGH PLAINS AND
MODELS INDICATE THAT THE MID AND UPPER-LEVEL RIDGE AXIS STARTS TO
SHIFT TO THE EAST WITH 30-40 METER 500 MB HEIGHT FALLS INDICATED
DURING THE DAY ON SUNDAY. MODELS...ESPECIALLY THE NAM...ARE WAY TO
MOIST GIVEN THE CURRENT CONDITIONS IN THE GULF AND OVER THE
SOUTHERN PLAINS...BUT NEVERTHELESS SOME INCREASE IN INSTABILITY
AND FORCING IS EXPECTED AND THIS WILL LIKELY LEAD TO A GOOD CHANCE
OF SHOWERS AND THUNDERSTORMS ON SUNDAY NIGHT. CURRENTLY WE FEEL
THE BETTER CHANCE OF SEVERE ACTIVITY WOULD BE SOUTHWEST OF OUR
AREA.

THE UPPER-LEVEL LOW PRESSURE IS EXPECTED TO DRIFT INTO NEB ON
MONDAY BECOMING NEARLY VERTICALLY STACKED WITH THE SURFACE LOW
OVER CENTRAL NEB. THE QUALITY OF THE MOISTURE WILL CONTINUE TO
INCREASE AHEAD OF THE SURFACE BOUNDARIES ON MONDAY...AND THIS WILL
LIKELY YIELD MLCAPE VALUES OF 1000-2000 J/KG BY EARLY AFTERNOON
OVER SOUTHEAST NEB AND SOUTHWEST IA. DEEP-LAYER SHEAR WILL
GENERALLY BE ON THE DECREASE ON MONDAY THOUGH AS THE BETTER MID
AND UPPER LEVEL FLOW SHIFT SOUTHEAST TOWARD THE BASE OF THE
TROUGH. THUNDERSTORMS MAY DEVELOP ALONG THE BOUNDARIES MONDAY
AFTERNOON...BUT CONFIDENCE IN PLACEMENT OF THE BOUNDARIES AND LOW
ARE HIGHLY UNCERTAIN AT THIS TIME...BUT SOME SEVERE WEATHER THREAT
DOES APPEAR POSSIBLE ON MONDAY...ESPECIALLY IN THE GFS/EC/GEM.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 PM CDT FRI MAY 6 2016

THE UPPER-LEVEL LOW WILL BE SLOW TO EXIT THE AREA WITH THE CHANCE
OF SHOWERS CONTINUING INTO MONDAY NIGHT AND TUESDAY BEFORE A
STRONGER COLD FRONT SWEEPS THROUGH THE AREA AND LEADS TO WHAT
LOOKS LIKE A DRY PERIOD FOR WEDNESDAY THROUGH FRIDAY...THOUGH THE
GLOBAL MODELS START TO SIGNIFICANTLY DIVERGE TOWARD THE END OF
THE PERIOD. THE EXTENDED TEMPERATURES WILL GENERALLY BE NEAR OR
SLIGHTLY BELOW NORMAL TO START THE PERIOD WITH THE UPPER LOW NEAR
THE AREA...BUT SHOULD MODERATE TOWARD THE END OF THE WEEK.

&&

.AVIATION...(00Z TAFS FOR KOMA...KLNK...KOFK THROUGH 00Z SUNDAY)
ISSUED AT 620 PM CDT FRI MAY 6 2016

A COLD FRONT WILL DROP THROUGH THE TAF SITES OVERNIGHT WHICH
SHOULD BRING AN INCREASE IN MID CLOUDS. AS SURFACE WINDS
DIMINISH THIS EVE...THE POTENTIAL FOR LOW LEVEL WIND SHEAR WILL
INCREASE AS A SOUTHWESTERLY LOW LEVEL JET INCREASES OVERNIGHT.
VFR CONDITIONS ARE EXPECTED OTHERWISE.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...BOUSTEAD
LONG TERM...BOUSTEAD
AVIATION...KERN



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