Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 301131 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
631 AM CDT TUE JUN 30 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT TUE JUN 30 2015

TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR SUGGEST THE
CONVECTION ACROSS CNTL SD COULD BRUSH BOYD COUNTY FOR A FEW HOURS
THIS MORNING. THIS CONVECTION WAS FORMING JUST BEHIND A COLD FRONT
WHICH WILL SAG PART WAY INTO THE FCST AREA THIS MORNING. LOW
PRESSURE ASSOCIATED WITH THE FRONT SHOULD DROP INTO SCNTL NEB THIS
AFTN AND THEN KS TONIGHT. THE FRONT AND UPPER/LOWER LEVEL MOISTURE
COULD MAKE FOR A FERTILE THUNDERSTORM ENVIRONMENT TONIGHT...MAINLY
NORTH OF NEBRASKA HIGHWAY 2 WHERE AMBIENT PWAT INCREASES TO 1.5
INCHES OR MORE.

SEVERE WEATHER POTENTIAL HINGES ON SOME VERY RICH MOISTURE ALOFT AT
500-100 MB AND THE POTENTIAL FOR STRONG DOWN DRAFTS WITH DRY AIR
BELOW THAT LEVEL. THIS SORT OF THING HAS BEEN COMMON ACROSS THE WRN
U.S. LATELY AND LATE THIS AFTN AND THIS EVENING COULD OUR TURN. SPC
SUGGESTED SWRN SD FOR SEVERE WEATHER.

THE TEMPERATURE FORECAST IS VERY MODEST GIVEN ALL MODELS SHOW THE
BANK OF CIRRUS ACROSS THE MT WILL MOVE INTO THE FCST AREA THIS
MORNING. 80S TO MID 90S IS TO BE EXPECTED. THE HIGH CLOUDS LIMIT
MIXING TO 700 MB AND SHOULD PREVENT SUPER ADIABATIC LAPSE RATES NEAR
THE SFC.

WINDS BACK AROUND TO THE NORTH TONIGHT WHICH COULD DRAW SMOKE INTO
THE FCST AREA. HUNDREDS OF WILDFIRES ARE BURNING ACROSS CNTL/WRN
CANADA AND ALASKA. LOWS FALL INTO THE 60S AND THE SREF SHOWS STRATUS
AROUND VALENTINE AND ONEILL BY MORNING.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 330 AM CDT TUE JUN 30 2015

UPPER LEVEL RIDGE REMAINS FIRMLY IN PLACE OVER THE INTERMOUNTAIN
WEST THROUGH MUCH OF THE LONG TERM PERIOD. DRY AND PARTLY CLOUDY
CONDITIONS EXPECTED WEDNESDAY WITH SUBTLE HEIGHT RISES AND LARGE
SCALE SUBSIDENCE IN THE WAKE OF A DEPARTING SHORTWAVE TROUGH. COLD
FRONT FROM TUESDAY WILL MODERATE TEMPERATURES SOMEWHAT...BUT
AFTERNOON MIXING TO AROUND 700MB WILL STILL LEAD TO A WARM DAY IN
SOUTHWEST NEBRASKA WITH HIGHS IN THE LOW TO MID 90S. FURTHER NORTH
AND EAST COOLER 850MB TEMPS WILL LIKELY KEEP HIGHS IN THE 80S.

THE NEXT IN THE SERIES OF SHORTWAVE TROUGHS TO TOP THE WESTERN CONUS
RIDGE BEGINS TO APPROACH THE CWA FROM THE NORTHWEST WEDNESDAY NIGHT.
LOW LEVEL FLOW BECOMES SOUTHERLY IN ADVANCE OF THE APPROACHING WAVE
WHICH WILL RETURN SURFACE DEWPOINTS INTO THE 60S. COLD FRONT SURGES
SOUTHEAST INTO THE CWA BY THURSDAY MORNING. MODELS SHOW CONVECTION
FIRING WEDNESDAY EVENING/NIGHT AS THE FRONT MOVES THROUGH WESTERN
SOUTH DAKOTA...EVENTUALLY MAKING IT INTO NORTHERN NEBRASKA BY
THURSDAY MORNING. ADDITIONAL DEVELOPMENT IS LIKELY BY EARLY
AFTERNOON AS THE MID-LEVEL CAP WEAKENS ALONG THE FRONT. THE SEVERE
THREAT REMAINS SOMEWHAT UNCLEAR AS MODELS CONTINUE TO FIGHT OVER THE
DEGREE OF DESTABILIZATION AHEAD OF THE FRONT. THE NAM IS THE MOST
AGGRESSIVE WITH BRINGING RICH SURFACE THETA-E AIR NORTHWARD AND
POOLING IT ALONG THE FRONTAL AXIS...LEADING TO SBCAPE VALUES
APPROACHING 3000 J/KG BY THE AFTERNOON. THE GFS IS A DRIER SOLUTION
AND MUCH LESS UNSTABLE. EITHER WAY...THE PRESENCE OF 35-45 KNOTS OF
DEEP LAYER SHEAR WILL PROMOTE THE POTENTIAL FOR AT LEAST A FEW
STRONG TO SEVERE STORMS BY THE TIME THE FRONT CLEARS THE CWA
THURSDAY NIGHT.

FORECAST TURNS DRY FOR FRIDAY AS THE UPPER LEVEL SHORTWAVE MOVES
SOUTHEAST. MODELS ARE IN FAIR AGREEMENT WITH A STRONG NORTHERN
STREAM UPPER LEVEL LOW DIGGING INTO CENTRAL CANADA OVER THE WEEKEND.
LOW LEVEL SOUTHERLY FLOW BECOMES REESTABLISHED ACROSS THE CENTRAL
CONUS IN RESPONSE TO A DEEPENING SURFACE LOW NEAR THE US/CANADIAN
BORDER. LOW LEVEL MOISTURE RETURN AND AMPLE SYNOPTIC SCALE LIFT WILL
SET THE STAGE FOR MORE THUNDERSTORM CHANCES AS A COLD FRONT MOVES
THROUGH THE CWA SUNDAY OR MONDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 631 AM CDT TUE JUN 30 2015

ISOLATED TO SCATTERED TSTM COVERAGE IS EXPECTED TODAY AND TONIGHT
WITH THE HIGHER COVERAGE EAST OF HIGHWAY 83 AND NORTH OF KBBW
TONIGHT. SOME STORMS THIS AFTERNOON AND EVENING MAY PRODUCE GUSTY
WINDS AND SIGNIFICANT OUTFLOW.

OTHERWISE VFR IS EXPECTED THROUGH 09Z. THEREAFTER THE SREF SUGGEST
THE POTENTIAL FOR IFR/MVFR CIGS GENERALLY ALONG AND NORTH OF
HIGHWAY 20 WEST OF VALENTINE.

&&

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

$$

SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CDC






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