Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 220532
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1232 AM CDT TUE APR 22 2014

.SYNOPSIS...
ISSUED AT 249 PM CDT MON APR 21 2014

SOUTH WINDS WILL RETURN MOISTURE NORTH THROUGH THE HIGH PLAINS
TUESDAY AND AN UPPER LEVEL DISTURBANCE MOVING OFF THE CNTL ROCKIES
WILL TRIGGER ISOLATED TSTMS TUESDAY AFTN AND TUESDAY NIGHT. A STRONG
PACIFIC COLD FRONT MOVES THROUGH WEDNESDAY FIRING OFF A SECOND ROUND
OF ISOLATED TO SCATTERED TSTMS WEDNESDAY AFTN AND EVENING.

THE LOW PRESSURE SYSTEM ASSOCIATED WITH THE UNSETTLED WEATHER
TUESDAY AND WEDNESDAY WILL MOVE INTO THE GREAT LAKES FRIDAY AND PULL
DOWN COLD AIR INTO THE FORECAST AREA. AT THE SAME TIME A DEEP
UPPER LEVEL LOW IS EXPECTED TO STALL ACROSS THE CNTL PLAINS AND
PRODUCE A CHANCE OF RAIN WITH MUCH COOLER TEMPERATURES FRIDAY NIGHT
THROUGH MONDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 249 PM CDT MON APR 21 2014

FOR TONIGHT SURFACE RIDGE OF HIGH PRESSURE WILL BUILD EAST WITH
BOUNDARY LAYER MOISTURE TO RECOVER. OVERNIGHT SURFACE WINDS VEER
TO SOUTHEAST...WHILE A SOUTHERLY H85 JET STREAK CRANKS UP TO 40 TO
50 KNOTS ACROSS THE WESTERN FORECAST AREA...IN AREAS GENERALLY
WEST OF HIGHWAY 83. FEW MID AND HIGH CLOUDS EXPECTED AS THE JET
STREAK DEVELOPS. CLOUD CEILINGS SHOULD BE AOB 10 KFT WITH LITTLE
IMPACTS SEEN OVERNIGHT. THE SOUTHERLY WINDS WILL INCREASE MIXING
THAT WILL ALSO KEEP LOW TEMPERATURES UP AND RANGING FROM THE UPPER
30S TO LOWER 40S AT DAYBREAK ON TUESDAY.

ON TUESDAY THE UPPER RIDGE BUILDS EAST ONTO THE WESTERN PLAINS WHILE
AT THE SURFACE THE DRYLINE DEVELOPS SOUTH ON THE HIGH PLAINS. THE
H85 SOUTHERLY JET STREAK SUSTAINS TO DRAW MOISTURE NORTH...YET THE
DRIER AIR IN PLACE WILL BE SLOW TO RECOVER DURING THE DAY. LOW POPS
INCLUDED FOR THE FAR WEST AS INSTABILITY INCREASES WITH THE HEATING
OF THE DAY AND EMBEDDED DISTURBANCES BEGIN TO EJECT NORTHEAST ACROSS
THE PLAINS. THUNDERSTORMS THAT DO FORM SHOULD BE HIGH BASED WITH
LITTLE TO NO PRECIP FOR THE LATE AFTERNOON. THE SHORT RANGE MODELS
DO SUGGEST THE MARGINAL INSTABILITY INTO THE LATE AFTERNOON AS THE
DRYLINE DEVELOPS SOUTH ON THE HIGH PLAINS TO RETAIN LOW POPS BUT CUT
BACK THE EASTERN EXTENT. TEMPERATURES TUESDAY WILL RANGE FROM THE
LOWER 70S NORTH CENTRAL TO MID 80S FAR WEST.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 249 PM CDT MON APR 21 2014

THE GFS AND NAM SUGGEST ONE OR 2 CLUSTERS OF THUNDERSTORMS MAY BE
ONGOING ACROSS WRN NEB TUESDAY EVENING. THE LOW LEVEL JET
INCREASING TO AROUND 50 KT IS EXPECTED TO SUSTAIN THE SRN MOST
CLUSTER OVERNIGHT AS IT MOVES EAST THROUGH THE FCST AREA.

THE 12Z MODEL RUNS OF THE NAM...ECM AND GFS SHOW THE STRONG PACIFIC
FRONT CLEAR OF THE FCST AREA BY 00Z WEDNESDAY EVENING. THE GEM IS
STILL BACK NEAR HIGHWAY 83 WHICH IS VERY SLOW LIKE IT SHOWED
YESTERDAY.

AT 18Z...NEAR NOONTIME WEDNESDAY...THE NAM SHOWS THE FRONT CLEAR OF
HIGHWAY 83 WHILE THE ECM...GFS AND GEM ARE FARTHER WEST. ONCE THIS
FRONT CLEARS THE AREA THE THREAT OF SEVERE WEATHER WILL END. THE
BEST CHANCE...AROUND 40 PERCENT...FOR SEVERE WEATHER WOULD APPEAR
ALONG AND EAST OF HIGHWAY 281 WEDNESDAY AFTERNOON BUT GIVEN THE
POSITION OF THE FRONT AT 18Z SHOWN BY THE SLOWER MODELS SEVERE
WEATHER COULD DEVELOP ALONG AND EAST OF HIGHWAY 83.

THE PACIFIC COLD FRONT MAY BE STRONG ENOUGH FOR SUSTAINED WINDS OF
30 MPH OR GREATER IN THE PANHANDLE WEDNESDAY AFTN AND THERE COULD
EVEN BE CRITICAL FIRE DANGER DEVELOPING GIVEN THE VERY LOW DEW POINT
AIR BEING ADVECTED IN OFF THE HIGH PLAINS.

ALL OR MOST OF THE TSTM ACTIVITY SHOULD EXIT THE FCST AREA BY
MIDNIGHT WEDNESDAY NIGHT. A CHECK ON THE SEVERE WEATHER PARAMETERS
APPEARS QUITE MARGINAL WITH VERY STRONG SHEAR RELATIVE TO THE AMOUNT
OF INSTABILITY AND THE BULK RICHARDSON NUMBERS HAVE FALLEN OFF BELOW
15 IN MOST AREAS AS INDICATED BY THE GFS AND NAM. STILL THERE COULD
BE OPPORTUNITIES FOR LOCAL AREAS OF MOISTURE CONVERGENCE WEDNESDAY
WHICH WOULD PRESENT FAVORABLE CONDITIONS FOR SEVERE STORM
DEVELOPMENT EAST OF HIGHWAY 83.

ALL OF THIS WEATHER CLEARS OUT BY THURSDAY MORNING LEAVING THE FCST
AREA IN A BELT OF COOL DRY PACIFIC AIR FOR SUNNY SKIES AND HIGHS IN
THE 60S. SOME SOLNS SUCH AS THE GEM AND GFS SHOW STRONG WINDS
CONTINUING THURSDAY AT 15 TO 25 MPH BUT THE ECM AND NAM BACK THESE
WINDS DOWN TO 15 TO 20 MPH.

THURSDAY NIGHT THROUGH MONDAY...
A HIGH LATITUDE BLOCK HAS FORMED SUPPORTING THE DEVELOPMENT OF
STRONG ARCTIC HIGH PRESSURE NORTH OF THE BEAUFORT COAST. IN TIME
THIS HIGH WILL DRIFT INTO MANITOBA AND ONTARIO AND GET PULLED SOUTH
INTO THE CNTL PLAINS AS LOW PRESSURE FORMS ACROSS THE CNTL ROCKIES.

A NEGATIVELY TILTED UPPER LOW WILL FORM ACROSS THE CNTL PLAINS BY
SUNDAY. ALL MODELS DEVELOP RAIN AND UPSLOPE WINDS THIS WEEKEND WHICH
COULD LAST INTO MONDAY. A BLEND OF THE MORNING RUNS OF THE
GFS...ECM...GEM AND DGEX SUGGESTED 1/2 TO 1 INCH OF RAIN DURING THIS
TIME WHICH IS CLOSE TO THE HPC FORECAST ISSUED LAST NIGHT. SO RAIN
IS QUITE POSSIBLE AS THIS UPPER LOW AND THE ARCTIC HIGH INTERACT
WITH GULF MOISTURE. WHAT REMAINS TO BE SEEN IS HOW MUCH OF THE
MOISTURE RETURNING NORTH BLOWS UP ACROSS OKLAHOMA AND KANSAS ROBBING
THE NRN STATES OF RAINFALL.

HIGHS IN THE 50S AND 60S FRIDAY SLIDE TO THE 40S BY MONDAY. LOWS ARE
EXPECTED TO REMAIN ABOVE FREEZING GIVEN THE H700MB FRONT IS LIFTING
SLOWLY NORTH DURING THIS TIME IN A WARM AIR ADVECTION PATTERN.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1232 AM CDT TUE APR 22 2014

VISUAL FLIGHT RULES THROUGH 06Z WEDNESDAY AT KVTN AND KLBF
TERMINALS. SURFACE RIDGE OF HIGH PRESSURE TO BUILD EASTWARD INTO
EASTERN NEBRASKA TUESDAY MORNING. SURFACE WINDS WILL BECOME
SOUTHEAST BY MORNING. WINDS TO INCREASE TO 17020G30KT BY 18Z AND
PERSIST THROUGH THE AFTERNOON. WINDS AFTER 02Z TO BE 15015G25KT.
ISOLATED THUNDERSTORMS DEVELOPING IN THE PANHANDLE MAY MOVE NEAR THE
KLBF TERMINAL TOWARD 03Z AND INTRODUCED VCTS.

&&

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

$$

SYNOPSIS...CDC
SHORT TERM...KECK
LONG TERM...CDC
AVIATION...ROBERG






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