Area Forecast Discussion
Issued by NWS North Platte, NE

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
000
FXUS63 KLBF 200536
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1236 AM CDT SUN APR 20 2014

.UPDATE...
ISSUED AT 846 PM CDT SAT APR 19 2014

UPDATE TO MAKE MINOR CHANGES TO PRECIPITATION FORECAST FOR THE
REST OF THE EVENING.

SHORT RANGE HIGH RESOLUTION MODELS STILL SUGGESTING A SMALL LINE
OF CONVECTION DEVELOPING ACROSS A PORTION OF CENTRAL NEBRASKA IN
THE NEXT FEW HOURS. RAP ANALYSIS SHOWS MID LEVEL FGEN INCREASING
ACROSS THE CENTRAL PART OF THE STATE...HOWEVER THIS IS AN AREA OF
MINIMUM LCL-LFC RH AS DEPICTED BY SPC MESOANALYSIS. IR PICS AND
OBS INDICATE BROAD MID LEVEL FORCING WITH MID CLOUDS MOVING
EASTWARD THIS EVENING AND ENHANCED SLIGHTLY IN FAVORED SYNOPTIC
GRAVITY WAVE GENERATION AREA...ALSO SEEN IN EARLIER VISIBLE SAT
IMAGES. DRY LAYER BELOW CLOUD BASE SO ANY PRECIP IS EVAPORATING
CURRENTLY...AND THIS IS CONFIRMED IN WEAK RADAR ECHOES AS WELL.
BELIEVE THE MID LEVEL FGEN WILL TIGHTEN AS THE EJECTING UPPER PV
ANOMALY CONTINUES TO MOVE NORTHEAST AND THIS AREA OVERLAYS BETTER
MOISTURE...WHICH SHOULD DEVELOP ISOLATED TSRA IN DECENT MID LEVEL
INSTABILITY AS INDICATED IN THE HRRR FOR EXAMPLE. QPF AMOUNTS WILL
BE LIGHT HOWEVER. REST OF THE FORECAST LOOKS IN GOOD SHAPE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 358 PM CDT SAT APR 19 2014

AN UPPER LEVEL LOW PRESSURE SYSTEM WILL TRACK FROM IT/S CURRENT
LOCATION IN SOUTHWEST NEW MEXICO...NORTHEAST TOWARD THE CENTRAL
PLAINS TONIGHT INTO SUNDAY. AT THE SURFACE A STATIONARY FRONT WILL
STRETCH FROM NEAR NORFOLK TO LEXINGTON TONIGHT...WITH THE FRONT
WASHING OUT/DISSIPATING LATE TONIGHT INTO SUNDAY. AS THIS
OCCURS...LIGHT EAST TO SOUTHEAST WINDS WILL DEVELOP...WHICH WILL
ADVECT LOW LEVEL MOISTURE BACK TO THE WEST/NORTHWEST INTO SOUTHWEST
THROUGH NORTH CENTRAL NEBRASKA. IN ADDITION...MOISTURE TRANSPORT
ALOFT INCREASES LATE TONIGHT INTO SUNDAY MORNING...WITH AN AREA OF
MID LEVEL FRONTOGENESIS DEVELOPING/STRENGTHENING SUNDAY MORNING FROM
ROUGHLY THE ONEILL AREA...SOUTHWEST TOWARD NORTH PLATTE AND
IMPERIAL. MODELS ARE SHOWING VERY LITTLE IN THE WAY OF QPF
OUTPUT...BUT JUST DON/T FEEL COMFORTABLE LEAVING FORECAST DRY DUE TO
THE ABOVE FACTORS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS MID
MORNING ONWARD ACROSS SOUTHWEST...CENTRAL AND EASTERN PORTIONS OF
NORTH CENTRAL NEBRASKA. BY AFTERNOON...DUE HAVE SOME INSTABILITY
DEVELOP DUE TO INCREASING MOISTURE AND HEATING...SO WILL INCLUDE A
MENTION OF THUNDER IN THE SAME AREA.

FARTHER NORTHWEST...A COLD FRONT WILL BE MOVING INTO NORTHWEST
NEBRASKA SUNDAY AFTERNOON. VERY STEEP 0 TO 3KM LAPSE RATES...OVER
9C/KM...ARE NOTED INVOF THE FRONT BY MID AFTERNOON. MID LEVEL LAPSE
RATES ARE DECENT...ON THE ORDER OF 7C/KM. AROUND 700J/KG OF
SURFACE BASE CAPE IS AVAILABLE...AND DO EXPECT AT LEAST ISOLATED
COVERAGE OF THUNDERSTORMS LATE IN THE AFTERNOON.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 358 PM CDT SAT APR 19 2014

SUNDAY NIGHT THROUGH TUESDAY...
ALL MODELS CONTINUE TO GENERATE LIGHT PRECIPE SUNDAY EVENING AS A
NORTHERN STREAM DISTURBANCE PASSES THROUGH SRN CANADA/NORTH DAKOTA.
MOISTURE FOR THIS RAIN IS QUESTIONABLE THE MOISTURE BELOW 700MB IS
GETTING SHUNTED EAST SUNDAY AFTERNOON SO SLIGHT CHANCE POPS ARE IN
PLACE FOR SUNDAY EVENING.

IN THE WAKE THE SUNDAY NIGHT...PACIFIC HIGH PRESSURES BUILDS INTO
THE FCST AREA MONDAY. THIS HIGH WILL BE PIVOTAL FOR MOISTURE RETURN
TUESDAY AND WEDNESDAY. WHAT IS SHOWN IS A COLD FRONT DROPPING INTO
THE EASTERN GULF AND RETURN FLOW DEVELOPING ACROSS WRN TEXAS
TUESDAY. THE MODELS ARE SHOWING SOUTH WINDS INCREASING TO AROUND 25
MPH ACROSS WRN NEB TUESDAY AND MOISTURE RETURNING UP THE CNTL AND
EVEN NRN HIGH PLAINS. AT THE SAME TIME WARM AIR ADVECTION WILL SURGE
EAST OFF THE CNTL ROCKIES AIMED AT THE CNTL/NRN HIGH PLAINS. THE
MODELS SHOW ISOLATED CONVECTION FIRING OFF THE COLO FRONT RANGE AND
LARAMIE RANGE TUESDAY AFTN WHICH COULD CARRY INTO THE FCST AREA
TUESDAY EVENING. ALL MODELS SHOW INSTABILITY DEVELOPING ALONG AND
WEST OF HIGHWAY 61 LATE TUESDAY WHICH COULD MAINTAIN THE CONVECTION
MOVING OFF THE MOUNTAINS.

HIGHS MONDAY RISE INTO THE 60S TO NEAR 70 WITH LIGHT NORTH WINDS.
HIGHS INCREASE TO THE 70S TUESDAY WITH WARMEST READINGS IN THE WEST.
SOUTH WINDS INCREASE TO 20 TO 30 MPH.

TUESDAY NIGHT THROUGH SATURDAY...
THE ISOLATED CONVECTION IN THE  WEST SHOULD DISSIPATE TUESDAY
EVENING. THE MODELS SHOW NOCTURNALLY DRIVEN CONVECTION REDEVELOPING
IN THE EAST AFTER MIDNIGHT...THE RESULT OF INCREASING MOISTURE
FORCED BY A 50 KT LOW LEVEL JET.

STRONG TO SEVERE STORMS CONTINUE TO BE INDICATED WEDNESDAY AFTERNOON
AND EVENING WITH THE BEST CHANCE EAST WHERE THE MOISTURE WOULD BE
DEEPEST. THE SPC OUTLOOK FOR WEDNESDAY CONTINUES ON TRACK. SOME
SOLNS LIKE THE GFS AND GEF ARE FARTHER WEST WITH THE DRYLINE BUT WE
WONT FOCUS ON LOCATION AS MUCH AS EVOLUTION AND THE MODELS CONTINUE
TO INDICATE A DEEP STREAM OF MOISTURE MOVING NORTH OUT OF THE GULF
WHICH INTERACTS WITH A DEEP UPPER LEVEL DISTURBANCE ACROSS THE NRN
PLAINS. MODEL TIMING OF THE MOISTURE RETURN VARIES WITH THE GFS AND
GEF FASTEST AND THE ECM AND GEM SLOWEST. THE FASTER MODELS GENERATE
MORE STORM COVERAGE.

THIS SYSTEM WILL MOVE VERY SLOWLY EAST WEDNESDAY THROUGH FRIDAY AND
PRODUCE STRONG SOUTH WINDS WEDNESDAY AND STRONG WEST AND NORTHWEST
WINDS THURSDAY AND PERHAPS FRIDAY.

HIGHS WEDNESDAY RISE INTO THE 70S TO AROUND 80 AND THEN COOL INTO
THE 50S AND 60S THURSDAY THROUGH SATURDAY. THE DISTURBANCE APPEARS
TO BE DEEP ENOUGH TO PULL SOME LATE SEASON ARCTIC AIR THROUGH THE
UPPER MIDWEST AND NORTHERN PLAINS WHICH SPILLS THROUGH THE FCST
AREA. THE ECM INCREASES RAIN CHANCES FRIDAY AND SATURDAY BUT THIS
HAS BEEN PUT ON HOLDING PENDING THE TIMING OF THAT SECOND SYSTEM.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1235 AM CDT SUN APR 20 2014

STATIONARY FRONT LOCATED FROM NORTHEAST NEBRASKA SOUTHWEST INTO
SOUTHEAST CO. SEVERAL PV ANOMALIES EJECTING NORTHEAST OUT OF
SOUTHWESTERN U.S. UPPER LOW ALLOWING ENHANCED LOW LEVEL CONVERGENCE
ALONG THE STALLED FRONT NOW ACROSS SOUTHWEST NEBRASKA. 20.03Z RAP
ANALYSIS SHOWING MID LEVEL FGEN TIGHTENING AS WAS EXPECTED THIS
EVENING AND INTERACTING WITH MID LEVEL INSTABILITY AS NOTED IN
MESOANALYSIS AND EVENING UPPER AIR. LLJ HAS INCREASED ACROSS CENTRAL
KS AND CENTRAL NEBRASKA...WITH KUEX INDICATING 50KTS IN THE 500M
LEVEL. THEREFORE ELEVATED CONVECTION HAS DEVELOPED AND HIGH
RESOLUTION MODELS HANDLED THIS FAIRLY WELL. CONVECTION WAS FIGHTING
DRY AIR INITIALLY. BELIEVE THIS MID LEVEL FORCING AND ASSOCIATED
INSTABILITY WILL REMAIN JUST EAST OF THE KLBF TAF SITE TONIGHT...AND
WELL SOUTH OF KVTN.

AS FOR SUNDAY...NEXT IN A SERIES OF PV ANOMALIES WILL MOVE NORTHEAST
OUT OF THE PREVIOUSLY MENTIONED UPPER LOW AND WORK WITH UNSTABLE AIR
TO DEVELOP ANOTHER AREA OF SHOWERS AND THUNDERSTORMS SUNDAY
AFTERNOON. HAVE LEFT MENTION OF SHRA/TSRA OUT OF THE KLBF TAF SITE
AT THIS POINT MAINLY DUE TO THE IDEA THAT THE BULK OF THE PRECIP
WILL BE IN THE MAIN ZONE OF WARM AIR ADVECTION WHICH AGAIN WILL BE
EAST OF THE SITE...THOUGH ISOLATED SHRA MAY DEVELOP FOR EITHER TAF
SITE...CONFIDENCE IN ANY AFFECTING TAF SITE SPECIFICALLY IS LOW.
COLD FRONT WILL MOVE SOUTHEAST THROUGH THE KVTN TAF SITE BY LATE IN
THE PERIOD...BUT AFTER THE PERIOD FOR KLBF.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JWS
SHORT TERM...TAYLOR
LONG TERM...CDC
AVIATION...JWS






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.