Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 271139 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
639 AM CDT WED APR 27 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM CDT WED APR 27 2016

TODAY AND TONIGHT...THE EXTENSIVE HEAVY THUNDERSTORM COVERAGE FROM
TEXAS TO IOWA HAS BLOCKED MOISTURE RETURN INTO WRN AND NCNTL NEB
EARLY THIS MORNING. THIS CONVECTION WILL MOVE OFF EAST LATER THIS
MORNING ALLOWING FOR A FRESH RETURN OF MOISTURE. THE SHORT RANGE
MODEL CONSENSUS SHOWS RAIN TODAY FROM ROUGHLY MERRIMAN TO BROKEN BOW
THIS MORNING WHICH SHIFTS NORTH FROM VALENTINE TO BURWELL THIS
AFTERNOON. THE WRAP AROUND RAIN SHOULD CONTINUE TO LIFT SLOWLY NORTH
TONIGHT.

THE FULL MODEL CONSENSUS OF 8 MODELS SUGGESTS A CLOSED H700MB LOW
WILL MOVE INTO SERN NEB THIS AFTERNOON AND INTO SWRN IOWA BY
THURSDAY MORNING. THIS IS CONSISTENT WITH THE RAIN LIFTING NORTH
THROUGH THE FCST AREA TODAY AND TONIGHT.

THE COLD AIR ALOFT COULD PRODUCE A MIX OF RAIN AND SNOW AT TIMES
WITH LESS THAN 1 AN INCH ACCUMULATION ACROSS NRN NEB. THE SFC LOW
MOVES VERY SLOWLY TODAY AND THIS COMBINED WITH H850MB WINDS NEAR
35KT WOULD SUPPORT FREQUENT GUSTS TO 35 MPH. HIGHS TODAY IN THE
LOWER 40S TO LOWER 50S REPRESENT A BLEND OF THE RAP AND THE PREVIOUS
FORECAST. THE RAP MAY BE TOO COLD SO THIS SOFTENS THE RAP SOLN.

LOWS TONIGHT MAY FALL BELOW FREEZING ACROSS NORTHERN NEB. H850MB
TEMPERATURES FALL BELOW FREEZING TONIGHT ACROSS ALL OF WRN AND NCNTL
NEB. WRAP AROUND CLOUDINESS SHOULD CONTINUE ACROSS NRN NEBRASKA
PREVENTING ANY SORT OF RADIATION CONDITION FROM DEVELOPING.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 347 AM CDT WED APR 27 2016

MID RANGE...THURSDAY AND FRIDAY... MAIN FORECAST CHALLENGES ARE
TEMPERATURES AND PRECIPITATION. THE UPPER LOW CURRENTLY OVER
SOUTHWEST NEBRASKA SLOWLY MOVES EAST WHILE ANOTHER UPPER LOW ROUNDS
THE TROUGH ACROSS THE WESTERN U.S.

MADE LITTLE CHANGE TO THURSDAY MAX TEMPS AS PREVIOUS FORECAST HIGHS
WERE SIMILAR TO THE 00Z MODEL SUITE. WITH NORTH/NORTHEAST LOW LEVEL
FLOW... SUBSTANTIAL CLOUD COVER... AND H85 TEMPS STAYING RANGING
FROM 0C TO 5C... FELT UPPER 40S TO MID 50S WERE REASONABLE. KEPT
PRECIP CHANCES ACROSS THE NORTHERN HALF OF THE CWA DUE TO MODEST MID
LEVEL FGEN FORCING AND MOISTURE AND WEAK LOW LEVEL LIFT. NAM
FORECAST SOUNDINGS INDICATE ALL SNOW FOR MUCH OF NORTHWEST AND NORTH
CENTRAL NEBRASKA THURSDAY MORNING... BUT LITTLE TO NO ACCUMULATION
IS EXPECTED. MOISTURE AND LIFT ARE WELL BELOW THE DGZ... AND WITH
TEMPS HOVERING NEAR FREEZING... SLRS WILL BE LOW. THE NEXT IMPULSE
ARRIVES LATE THURSDAY NIGHT AHEAD OF THE SECOND UPPER LOW. MID LEVEL
FGEN AND MOISTURE INCREASE FROM THE SOUTHWEST GENERALLY AFTER 00Z
FRIDAY. INCLUDED A THUNDER MENTION BEFORE 06Z SOUTH OF I-80 AS NAM
SHOWS LIMITED CAPE... SUFFICIENT DEEP LAYER SHEAR... AND MID LEVEL
LAPSE RATES NEAR 7C/KM. THU NIGHT MIN TEMPS DROP BELOW FREEZING
ACROSS FAR NORTHWEST NEB... MAINLY SHERIDAN COUNTY. HOWEVER...
FORECAST SOUNDINGS ARE NOT CLEAR ON THE POTENTIAL FOR ALL SNOW... SO
LEFT PTYPE AS RASN FOR NOW.

FOR FRIDAY... LOWERED MAX TEMPS A DEGREE OR SO AS RENEWED CAA
RESULTS IN THE HIGHEST H85 TEMPS OF ONLY 3C. WIDESPREAD PRECIP AND
CONTINUED NORTHEAST FLOW WILL ALSO BE LIMITING FACTORS FOR
TEMPERATURES. IN ADDITION TO MID LEVEL FRONTOGENESIS AND SATURATION
ACROSS THE AREA... BROAD ISENTROPIC LIFT IS EVIDENT AT 295K AND
300K. NAM SOUNDINGS HINT AT PERIODS OF FAIRLY STRONG LIFT IN THE
LOWER AND MID LEVELS WITH OMEGA SURPASSING -20US. COULD BE LOOKING
AT 24 HR PRECIP TOTALS NEAR ONE INCH ENDING 12Z SATURDAY... WHICH IS
CLOSE TO WPC GUIDANCE. ENSEMBLES ALSO SHOW PWAT VALUES ABOUT 1 STDEV
ABOVE CLIMO. FRIDAY NIGHT... TEMPS AGAIN DROP TO NEAR FREEZING
ACROSS SHERIDAN COUNTY BUT LEFT PTYPE AS RASN AS RELATIVE WARM AIR
EXISTS TO 750HPA.

LONG RANGE...SATURDAY THROUGH TUESDAY... SIGNIFICANT DIFFERENCES
EXIST BETWEEN GFS AND EURO REGARDING THE PLACEMENT OF THE H5 LOW AND
H3 JET. HOWEVER... BOTH KEEP A LARGE TROUGH OVER THE WESTERN U.S.
AND A PROGRESSION OF SHORTWAVES THROUGH THE AREA. FELT CONFIDENT
ENOUGH TO CONTINUE LIKELY/DEFINITE POPS SATURDAY GIVEN DECENT
MOISTURE DRAW AHEAD OF THE SFC LOW. TAKING A BLEND OF THE DEW
POINTS... LOWER 40S RESULT FOR THE EASTERN HALF OF THE CWA. ALSO
KEPT THUNDER MENTION DUE TO SOME ELEVATED INSTABILITY. AFTER
SUNDAY... CAPPED POPS TO CHC DUE TO TIMING/PLACEMENT ISSUES BUT
ENOUGH OF A SIGNAL REMAINS TO CONTINUE PRECIP MENTION. GRADUAL
WARMING AT H85 OCCURS THROUGH MIDWEEK WITH TEMPS APPROACHING 7C BY
TUESDAY EVENING. OVERALL... EXPECTING A COOLER THAN AVERAGE EXTENDED
PERIOD WITH HIGHS MAINLY IN THE 40S AND 50S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 638 AM CDT WED APR 27 2016

MIXED LIFR/IFR/MVFR AND VFR CIGS CONTINUE THIS MORNING WITH
IMPROVEMENT TO IFR/MVFR AND VFR THIS AFTN. THE LOWEST CIGS ARE
ASSOCIATED WITH THE RAIN SHEILD WHICH WILL LIFT SLOWLY NORTH THIS
MORNING AND THIS AFTERNOON. A SECOND AREA OF LOW CIGS SHOULD
DEVELOP THIS EVENING ACROSS NRN NEB...ALONG HIGHWAY 20. AREAS
SOUTH OF HWY 20 SHOULD EXPERIENCE MVFR/VFR CIGS TONIGHT.

&&

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

$$

SHORT TERM...CDC
LONG TERM...SNIVELY
AVIATION...CDC



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