745 FXUS63 KLBF 200958 AFDLBF AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTH PLATTE NE 358 AM CST TUE NOV 20 2012 .DISCUSSION... PRIMARY FORECAST CONCERNS THROUGH THE NEXT WEEK ARE TEMPERATURES...THEN WITH PRECIPITATION CHANCES NEXT WEEK. AT 08Z...A DISTINCT SHORTWAVE TROUGH WAS SEEN ON WATER VAPOR IMAGERY GOING ACROSS NEBRASKA. MEANWHILE...SHORTWAVE RIDGING WAS INDICATED UPSTREAM INTO THE NORTHERN ROCKIES WHILE A LARGE TROUGH WAS IN PLACE OVER THE NORTHERN PACIFIC. ALSO...A WEAK UPPER LOW WAS LOCATED OFF BAJA CALIFORNIA. LOCALLY...HIGH PRESSURE HAD BUILT INTO THE REGION OVERNIGHT AS THE COLD FRONT ASSOCIATED WITH THE UPPER LEVEL SHORTWAVE HAD PUSHED ACROSS KANSAS AND INTO MISSOURI. WITH LITTLE CLOUD COVER AND LIGHT WINDS...TEMPERATURES HAD DROPPED INTO THE 20S ACROSS MUCH OF THE FORECAST AREA EARLY THIS MORNING. .SHORT TERM...TODAY THROUGH THURSDAY NIGHT FOR TODAY...AS THE SHORTWAVE DIGS FURTHER INTO THE MID MISSISSIPPI VALLEY RIDGING WILL BUILD INTO THE NORTHERN AND CENTRAL PLAINS. WARM AIR ADVECTION WILL BE OCCURRING THROUGH THE DAY AS 850MB TEMPERATURES RISE TO NEAR 15C IN PLACES. SHOULD SEE DECENT MIXING THIS AFTERNOON SO LOOKING LIKE UPPER 60S AND EVEN LOW 70S WILL BE LIKELY ACROSS THE REGION. IN ADDITION TO THE WARM TEMPERATURES...WINDS SHOULD BE FAIRLY BREEZY SOUTH OF THE SOUTHWEST THIS AFTERNOON. ON WEDNESDAY A SHORTWAVE TROUGH WILL MOVE INTO THE PACIFIC NORTHWEST...AND AS THE SHORTWAVE DOWNSTREAM OF THE LOCAL AREA CONTINUES TO DIG TO THE SOUTHEAST...UPPER LEVEL RIDGING WILL SHIFT INTO THE MISSISSIPPI RIVER VALLEY. THE COLD FRONT WITH THIS NEXT SYSTEM WILL REMAIN OFF TO THE WEST ON WEDNESDAY THOUGH SO TEMPERATURES WILL AGAIN BE QUITE WARM. WENT WITH THE HIGHER END OF FORECAST GUIDANCE FOR HIGHS WITH GOOD MIXING EXPECTED AND THE TREND WITH THE DRY CONDITIONS HAS BEEN TO GO WARM. THE COLD FRONT WILL MOVE THROUGH THE FORECAST AREA WEDNESDAY NIGHT AND THURSDAY MORNING. THERE IS STILL SLIGHT DIFFERENCES IN THE TIMING OF THE FRONT...BUT IT SHOULD BE THROUGH BY 15Z ON THURSDAY. THE COLD AIR ALOFT WILL BE SLIGHTLY BEHIND THE SURFACE FRONT...BUT BY 00Z FRIDAY THE ENTIRE FORECAST AREA SHOULD HAVE 850MB TEMPERATURES BELOW 5C. ALTHOUGH COLD AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...NOT EXPECTING A NON-DIURNAL TEMPERATURE TREND...JUST DON/T EXPECT A GOOD WARM UP. SO DID DROP TEMPERATURES A BIT FROM THE PREVIOUS FORECAST. NEAR 50 LOOKS MORE LIKELY OVER NORTHWEST NEBRASKA...WITH UPPER 50S TO NEAR 60 OVER SOUTH CENTRAL NEBRASKA. ALSO...A STRONG PRESSURE GRADIENT WILL BE OVER THE AREA BEHIND THE FRONT SO LOOKING AT STRONG WINDS THROUGHOUT THE DAY. COULD SEE GUSTS ABOVE 30KTS AT POINTS DURING THE DAY. VERY LITTLE MOISTURE WILL BE ASSOCIATED WITH THIS FRONT...SO FORECAST REMAINS DRY THROUGH THE THANKSGIVING HOLIDAY. MAY SEE SOME MID AND HIGH LEVEL CLOUDS ON THURSDAY...BUT SKIES SHOULD STAY PARTLY TO MOSTLY CLOUDY. WITH LOW TEMPERATURES...TRENDED LOWS DOWN EACH NIGHT. LIGHT WINDS AND CLEAR SKIES TONIGHT SHOULD ALLOW FOR GOOD RADIATIONAL COOLING AND DROP LOWS INTO THE MID 20S...ESPECIALLY IN DRAINAGE AREAS. WITH WINDS INCREASING BEHIND THE COLD FRONT AND WITH THE COLD AIR LAGGING...TEMPERATURES MAY STAY UP A BIT...HOWEVER LOCATIONS AHEAD OF THE FRONT COULD SEE A QUICK DROP PRIOR TO FRONTAL PASSAGE. THEN ON THURSDAY NIGHT AS 850MB TEMPERATURES DROP BELOW 0C /NEAR -10C IN NORTH CENTRAL NEBRASKA/ SHOULD GET LOWS CONSIDERABLY COOLER. DROPPED LOWS INTO THE TEENS AND LOW 20S MOST PLACES...BUT WILL NEED TO WATCH THE TREND IN WINDS IN THE NEXT SEVERAL FORECASTS. IF THE HIGH BUILDS IN FASTER COULD GET WINDS TO DROP OFF AND TEMPERATURES TO GET COLDER YET. .LONG TERM...FRIDAY THROUGH TUESDAY TEMPERATURES WILL BE THE PRIMARY FORECAST FOCUS THROUGH THE WEEKEND. THE SHORTWAVE TROUGH AND FRONTAL SYSTEM THAT MOVE THROUGH WEDNESDAY AND THURSDAY WILL PROGRESS EAST ON FRIDAY AND SATURDAY ALLOWING HIGH PRESSURE TO BUILD INTO THE PLAINS AND TAKE RESIDENCE THROUGH FRIDAY NIGHT. THE HIGH WILL SHIFT EAST ON SATURDAY BRING RETURN FLOW BACK INTO THE PLAINS AS RIDGING ALOFT BUILDS BACK EASTWARD. THIS WILL BRING A GRADUAL UPWARD TREND IN TEMPERATURES...HOWEVER IT WILL TAKE A FEW DAYS AS THE COLD AIR WILL KEEP INFLUENCE ON TEMPERATURES FOR FRIDAY AND SATURDAY. FRIDAY/S HIGHS WERE LOWERED A FEW DEGREES...LOOKING TO TOP OUT ONLY IN THE UPPER 30S AND 40S. SATURDAY WILL BE A BIT WARMER WITH UPPER 40S AND 50S. THE NEXT SIGNIFICANT SYSTEM TO WATCH WILL BE A SHORTWAVE TROUGH MOVING INTO THE PACIFIC NORTHWEST ON SUNDAY. THERE HAS BEEN CONSIDERABLE MODEL DIFFERENCES WITH THE STRENGTH AND PROGRESSION OF THIS SYSTEM. PRIOR RUNS OF THE ECMWF HAD IT AMPLIFYING AS IT CROSSES THE ROCKIES AND WOULD/VE BROUGHT A DECENT CHANCE FOR A FRONTOGENETICAL BAND OF PRECIPITATION TO SOME PORTION OF NEBRASKA. THE LATEST DETERMINISTIC RUN IS MORE IN LINE WITH THE GFS SOLUTION WHICH KEEPS THE SYSTEM QUICKER AND LESS AMPLIFIED. THIS WOULD STILL BRING A SHOT FOR SOME SNOW TO THE PANHANDLE AND INTO WESTERN NEBRASKA ON MONDAY AND MONDAY NIGHT WITH UPSLOPE FLOW AND MOISTURE ADVECTION INTO THESE AREAS. BUT THE FORCING QUICKLY DIMINISHES...WITH CHANCES GOING DOWN INTO THE DAY TUESDAY. DID KEEP THE MENTION OF SNOW INTO THE FORECAST INTO TUESDAY DUE TO THE UNCERTAINTY OF THE MODEL SOLUTIONS...AND AS THERE HAS BEEN AN INDICATION OF A STRONGER SHORTWAVE MOVING THROUGH TO IMPACT THE FORECAST AREA. CONFIDENCE IS QUITE LOW THOUGH THROUGH THIS PERIOD SO KEPT CHANCES ON THE LOW END FOR NOW. IN TERMS OF LOW TEMPERATURES...TRENDED THEM DOWN THROUGHOUT THE PERIOD AS THE CONSENSUS SOLUTIONS HAVE BEEN TOO WARM OVER THE PAST SEVERAL MONTHS. TRENDED LOWS TO THE LOWER END OF GUIDANCE...ESPECIALLY AS THE COLDER AIRMASS IS COMING INTO THE REGION. THESE MAY BE SLIGHTLY WARM STILL SO WILL KEEP AN EYE ON THEM IN FUTURE FORECASTS. && .AVIATION... A WARM FRONT DEVELOPING OVER THE DAKOTAS AND A SURFACE TROUGH ACROSS WESTERN NEBRASKA WILL BRING A RETURN OF SOUTHWEST FLOW WITH WIND BECOMING 190-220 AT 10-12G18-20KT BY 17Z IN WESTERN AND NORTH CENTRAL NEBRASKA. WITH DRY AIR IN THE NEAR SURFACE LAYER...DEWPOINTS IN THE TEENS WILL KEEP FOG FROM DEVELOPING OVER THE AREA. THERE IS ALSO NO MECHANISM FOR BRINGING MOISTURE INTO THE AREA AT LOW LAYERS JUST ABOVE THE SURFACE. AS A RESULT...NO RESTRICTIVE CEILING OR VISIBILITY IS EXPECTED THROUGH EARLY WEDNESDAY. && .FIRE WEATHER... ALTHOUGH CONDITIONS WILL NOT BE TO RED FLAG CRITERIA TODAY...WITH RH/S BOTTOMING OUT AROUND 20 PERCENT AND WINDS GUSTING IN THE LOW 20S...FIRE WEATHER CONDITIONS WILL AGAIN BE ELEVATED. FIRE CONDITIONS WILL ALSO BE HIGH ON WEDNESDAY WITH RELATIVE HUMIDITY DROPPING INTO THE TEENS ACROSS MUCH OF THE FORECAST AREA AS TEMPERATURES RISE INTO THE UPPER 60S AND LOW 70S. WINDS ARE NOT FORECAST TO BE TO THE STRENGTH NEEDED FOR RED FLAG CONDITIONS...BUT WILL KEEP A CLOSE WATCH ON THIS PERIOD IN UPCOMING FORECASTS. ON THURSDAY...RELATIVE HUMIDITY WILL NOT BE AS LOW...WITH MINIMUM READINGS EXPECTED BETWEEN 20 AND 30 PERCENT. HOWEVER...WITH NORTH TO NORTHWEST WINDS BLOWING TO 30 MPH FIRE BEHAVIOR COULD BE EXTREME. .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...BROOKS AVIATION...SPRINGER