Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 250857
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
357 AM CDT MON AUG 25 2014

.SYNOPSIS...
ISSUED AT 356 AM CDT MON AUG 25 2014

A SECONDARY COLD FRONT HAS PUSH INTO THE CENTRAL FORECAST AREA THIS
MORNING AND WILL PUSH THROUGH THE REMAINDER OF THE AREA BY DAYBREAK.
DEWPOINTS RANGING IN THE 40S ACROSS THE PANHANDLE INTO MOST OF NCTRL
NEBR TO THE MID 50S FURTHER SOUTHEAST. SCATTERED SHOWERS AND
THUNDERSTORMS CLUSTERED IN NWRN KS FAR SWRN NEBR...WHILE OTHERS
EXTEND WEST ACROSS NRN CO...SRN WY AND NRN UTAH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT MON AUG 25 2014

FOR TODAY...

A DISTURBANCE CURRENTLY IN CENTRAL CO AND ANOTHER DISTURBANCE
LOCATED IN NERN UTAH WILL BOTH LIFT NORTHEAST TODAY THROUGH WESTERN
NEBRASKA. SHOWERS AND A FEW THUNDERSTORMS JUST BEGINNING TO MOVE
THROUGH CHASE INTO HAYES COUNTY. THERE WILL BE A 30 PERCENT CHANCE
THROUGH TODAY...EXCEPT SLIGHT CHC IN THE ERN PANHANDLE. THE SYSTEM
IN NERN UTAH APPEARS THE STRONG ONE. HOWEVER MODELS DIFFER ON DEGREE
OF MOISTURE AND LIFT. COVERAGE SHOULD BE SCATTERED AT BEST WITH
RESULTING QPFS LIGHT...RANGING ONLY UP TO A TENTH OF AN INCH MOST
AREAS. SKIES TO TURN MOSTLY CLOUDY THIS MORNING...THEN PARTLY CLOUDY
IN THE AFTERNOON. HIGHS TODAY COOLER THAN THE PAST SEVERAL...IN THE
MID 70S...EXCEPT NEAR 80 FAR SOUTHERN AREAS.

FOR TONIGHT...

MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A MID LEVEL DISTURBANCE
CURRENTLY LOCATED IN WESTERN ARIZONA LIFTING NORTHEAST INTO CENTRAL
COLORADO BY 00Z TUESDAY. THE SURFACE FRONT LOCATED FROM NWRN KS INTO
SERN NEBR WILL REMAIN FAIRLY STATIONARY WITH EASTERN UPSLOPE WINDS
ACROSS WRN NEBR. FORECAST MODELS HAVE BEEN FAIRLY CONSISTENT WITH
THUNDERSTORMS FOCUSED ACROSS THE SOUTHEASTERN HALF OF FA TONIGHT. THE
ECMWF HAS THE HIGHEST OUTPUT OF QPFS WITH HIGHER AMOUNTS FROM 1/2
INCH TO 1 INCH. HAVE POPS INCREASING TO LIKELY BY LATE EVENING SOUTH
OF AN OGA THROUGH ONL LINE...INCREASING TO NEAR 80 POPS AFTER
MIDNIGHT. NORTH OF THIS LINE...MODELS HAVE MUCH LESS FOCUS...WITH
POPS RANGING FROM 30 TO 50 PERCENT. CONTINUED MENTION OF HEAVY
RAINFALL ACROSS SERN COUNTIES IN THE GRIDDED FORECAST DESPITE WPC
DAY1 EXCESSIVE RAINFALL SLIGHT RISK AREA REMOVED.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 356 AM CDT MON AUG 25 2014

THE FORECAST FOR THIS PORTION OF THE FORECAST CONTINUES TO BE
FOCUSED ON RAIN CHANCES AND THE POTENTIAL FOR HEAVY RAIN FROM
TUESDAY...AND NOW THROUGH WEDNESDAY NIGHT.

THE PRIMARY UPPER LEVEL TROUGH WILL BE WELL OFF TO THE WEST...OVER
THE GREAT BASIN AT THE BEGINNING OF THE DAY TUESDAY. SEVERAL
PIECES OF ENERGY WILL EJECT OUT OF THE MAIN SYSTEM AND PUSH
NORTHEAST THROUGH THE MID LEVEL FLOW THROUGH THE WEEK. THE FIRST
OF THESE IMPULSES WILL MOVE ACROSS WESTERN KANSAS AND SOUTHERN
NEBRASKA TONIGHT...AND AFTER RAIN ASSOCIATED WITH THIS SHORTWAVE
TROUGH IS LIKELY TONIGHT...THERE SHOULD BE A BREAK FROM THE
PRECIPITATION DURING THE DAY ON TUESDAY. THERE IS QUITE A BIT OF
UNCERTAINTY DUE TO SPREAD IN THE MODEL SOLUTIONS WITH HOW THINGS
WILL PLAY OUT ON TUESDAY. THE SHORTWAVE TROUGH WILL PUSH OFF TO
THE EAST THROUGH THE DAY...WHILE THE NEXT SHORTWAVE MOVES OUT OF
THE SOUTHWEST AND INTO COLORADO BY THE AFTERNOON. MOISTURE WILL
REMAIN ACROSS THE AREA BUT WITH THE AMOUNT OF LIFT DIMINISHING IN
THE SHORTWAVE RIDGING REGIME THROUGH THE DAY THE PRECIPITATION
SHOULD BECOME LESS WIDESPREAD. THE MAJORITY OF THE MODELS ARE
INDICATING THERE WILL BE AT LEAST SOME WEAK CONVECTION THROUGH THE
DAY AND WITH THE DIFFERENCES IN MODEL SOLUTIONS DIDN/T VENTURE TOO
FAR FROM THE PREVIOUS FORECAST. HOWEVER...DID LOWER CHANCES A
BIT...AND IF THE NAM IS CORRECT CHANCES MAY NEED TO BE LOWERED
FURTHER.

FOR TUESDAY NIGHT...THE UPPER LEVEL SHORTWAVE TROUGH MOVES INTO
COLORADO AND THEN NEBRASKA BUT EARLY WEDNESDAY MORNING. THE LOW
LEVEL JET INCREASES SUBSTANTIALLY OVERNIGHT WHICH IS FOCUSED INTO
SOUTHWEST NEBRASKA. THIS FLOW LIFTS RIGHT OVER THE WARM FRONT
WHICH IS ORIENTED WEST TO EAST FROM AROUND EAST CENTRAL COLORADO
THEN ACROSS SOUTHERN NEBRASKA. THE LOW LEVEL JET DOESN/T BEGIN TO
VEER OFF TO THE EAST UNTIL LATE /AROUND 09Z/ SO ALTHOUGH ACTIVITY
SHOULD MOVE OFF TO THE NORTHEAST...EXPECT ACTIVITY TO CONTINUE TO
DEVELOP JUST NORTH OF THE FRONT FOR MUCH OF THE NIGHT. IF THIS
PLAYS OUT IN THIS MANNER...SOME LOCATIONS COULD SEE HEAVY RAINFALL
WITH TRAINING THUNDERSTORMS. IN ADDITION TO THE THREAT FOR
TRAINING THUNDERSTORMS...THESE STORMS ARE EXPECTED TO BE
EFFICIENT RAINFALL PRODUCERS AS FORECAST SOUNDINGS LOOK QUITE
TROPICAL IN NATURE...WITH ALMOST THE ENTIRE COLUMN
SATURATED...TALL SKINNY CAPE...AND A DEEP WARM CLOUD LAYER. THESE
SOUNDINGS SEEM REALISTIC AS THE REGION WILL HAVE MOISTURE
ADVECTION ONGOING IN MULTIPLE LEVELS...FROM THE EAST AT THE
SURFACE /WHERE DEWPOINTS ARE EXPECTED TO BE IN THE UPPER 60S AND
70S/...FROM THE 850-700MB LAYER /WHERE MOISTURE WILL BE PULLED
NORTHWARD ACROSS THE HIGH PLAINS FROM THE GULF OF MEXICO...AND IN
THE MID AND UPPER LEVELS...FROM THE MONSOONAL FLOW OFF THE PACIFIC
COAST.

THE SHORTWAVE TROUGH IN THE MID LEVELS FROM TUESDAY NIGHT WILL
MOVE VERY SLOWLY ON WEDNESDAY AS THE REGION SITS IN AN AREA OF
LOW FLOW ALOFT. WITH THIS PACE...WOULD EXPECT QUITE A BIT OF
WIDESPREAD RAIN DURING THE DAY WEDNESDAY. ON WEDNESDAY NIGHT THE
MAIN UPPER LEVEL SYSTEM BEGINS TO MOVE CLOSER TO THE AREA AS IT
PUSHES INTO THE CENTRAL ROCKIES /INTO COLORADO AND SOUTHERN
WYOMING. WEAK SHORTWAVE TROUGHS WILL CONTINUE TO PEEL OFF THE MAIN
SYSTEM AND THE MODELS ARE PUSHING ANOTHER SYSTEM ACROSS NEBRASKA
OVERNIGHT. ANOTHER CASE OF THE LOW LEVEL JET WILL BE SEEN THROUGH
THURSDAY MORNING WHICH SHOULD BRING ADDITIONAL CHANCES FOR RAIN
OVERNIGHT. WITH THE SAME BASIC SET UP...INCLUDED MENTION OF
LOCALLY HEAVY RAIN IN THE FORECAST FOR WEDNESDAY NIGHT.

THE UPPER LOW WILL START TO PROGRESS EAST THROUGH THE LATTER HALF
OF THE WEEK AND ALTHOUGH PRECIPITATION CHANCES WILL CONTINUE FOR
PORTIONS OF THE FORECAST AREA /PRIMARILY THE SOUTHEAST HALF AS
ENERGY CONTINUES EJECTING OUT OF THE MAIN SYSTEM/ THE TRAJECTORY
OF THESE SYSTEMS WILL BEGIN GOING EAST OF THE AREA SO HAVE
CONTINUED THE DIMINISHING TREND IN PRECIPITATION CHANCES THROUGH
THE WEEK. THE MODELS ARE COMING TOGETHER IN TERMS OF THE
PROGRESSION OF THE UPPER LEVEL LOW...WITH THE SLOWER SOLUTION
SEEMING TO BE THE PREFERRED SOLUTION. AGAIN...THIS SLOWER
PROGRESSION WILL KEEP PRECIPITATION CHANCES ACROSS MUCH OF THE
AREA THROUGH THE MUCH OF THE SECOND HALF OF THE WORK WEEK.

LOOKING AT TEMPERATURES...THIS SYSTEM IS QUITE COLD AS 850MB
TEMPERATURE DROP DOWN TO AROUND 10C ON CERTAIN DAYS. ALSO OF
NOTE...THIS SYSTEM DID PRODUCE SNOW ACROSS PORTIONS OF WESTERN
MONTANA ON SUNDAY. THE COLD AIR...COMBINED WITH THE RAIN AND HIGH
AMOUNT OF CLOUD COVER EXPECTED TUESDAY THROUGH FRIDAY HAVE KEPT
HIGHS BELOW NORMAL...IN THE 70S AND LOW 80S ACROSS THE FORECAST
AREA. BY THE WEEKEND...ASSUMING THE UPPER LEVEL LOW SYSTEM
FINALLY MOVES EAST...THE WEATHER SHOULD BE DRY AS WEAK RIDGING
BUILDS IN AND TEMPERATURES SHOULD GET BACK ON AN UPWARD TREND WITH
GENERALLY 80S IN THE FORECAST FOR THE WEEKEND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1125 PM CDT SUN AUG 24 2014

A DISTURBANCE ACROSS NRN COLORADO/SRN WY IS EXPECTED TO PRODUCE
SCATTERED SHOWERS AND ISOLATED STORMS OVERNIGHT THROUGH EARLY
MONDAY AFTN. INDICATIONS IN THE MODELS IS FOR VFR/LOCAL MVFR/IFR
CIGS AND VSBY AS THIS RAIN MOVES THROUGH.

ADDITIONAL TSTM ACTIVITY IS EXPECTED TO DEVELOP MONDAY EVENING
ACROSS SWRN NEB.


&&

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

$$

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







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