National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KLBF 171128
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
628 AM CDT FRI MAY 17 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 355 AM CDT FRI MAY 17 2013

AN UPPER TROUGH ACROSS THE INTERMOUNTAIN WEST AND A SURFACE
TROUGH ALONG THE HIGH PLAINS WILL BRING A SHARP WARMUP TO THE
CENTRAL PLAINS REGION TODAY. ACROSS WESTERN NEBRASKA...SOUTH WINDS
WILL INCREASE TO 15 TO 25 MPH THIS AFTERNOON. THE LACK OF A
WESTERLY COMPONENT...EVEN IN THE EASTERN PANHANDLE WILL HELP KEEP
DEWPOINTS SUSTAINED IN THE UPPER 40S EASTERN PANHANDLE WITH UPPER
50S CENTRAL AND EASTERN AREAS. DEEP VERTICAL MIXING TO RESULT IN
HIGHS REACHING THE UPPER 80S...WITH NEAR 90 WESTERN COUNTIES.
SKIES LOOK TO BE MOSTLY SUNNY TODAY. A WEAK DISTURBANCE INDICATED
BY THE MODELS IN AMPLIFIED MID AND UPPER LEVEL FLOW WILL BRING 20
TO 30 POPS TO NORTHWESTERN/WESTERN AREAS LATE THIS AFTERNOON.
MUCAPES 0-3KM INCREASE QUICKLY THIS AFTERNOON REACHING 2000-3000
J/KG. MUCH OF THE AREA WILL REMAIN CAPPED TODAY...EXCEPT FOR AREAS
WEST OF VALENTINE THROUGH OSHKOSH LATE THIS AFTERNOON. DEEP LAYER
SHEAR OF 30-35KT SUPPORTIVE OF A FEW STRONG THUNDERSTORMS WITH
SMALL HAIL AND GUSTY WINDS. STORM MOTION IS TO THE EAST NORTHEAST
AT 20KT THIS EVENING...THEREFORE EXTENDED SLIGHT CHANCES AS FAR
EAST AS A BUTTE THROUGH THEDFORD THIS EVENING. AND DESPITE A
CAPPED ATMOSPHERE FURTHER SOUTH...ISOLATED STORM ARE POSSIBLE EVEN
INTO SOUTHWEST NEBRASKA LATE AFTERNOON AND EVENING AND INTRODUCED
MENTION TO THIS AREA. A STRONG LOW LEVEL JET WILL PROVIDE THE BEST
CHANCES FOR THUNDERSTORMS OVERNIGHT TO PORTIONS OF SOUTH
DAKOTA...AND POSSIBLY FAR NORTHERN NEBRASKA...SO KEPT MENTION FOR
A SLIGHT CHANCE GOING THERE AFTER MIDNIGHT. DEWPOINTS OVERNIGHT
WILL REMAIN IN THE 50S TO NEAR 60 WITH SOUTH WINDS 10 TO 20 MPH.
LOWS SHOULD ONLY FALL TO THE LOWER 60S MOST AREAS. IN
ADDITION...STRATUS IS LIKELY TO ADVECT INTO THE AREA AFTER
MIDNIGHT. WHILE PATCHY FOG IS ALSO POSSIBLE... ADEQUATE MIXING
WILL LIMIT THE POTENTIAL SO DID NOT MENTION AT THIS TIME.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 355 AM CDT FRI MAY 17 2013

MAIN FORECAST CONCERNS THROUGH THIS PERIOD ARE SEVERE STORM
CHANCES FOR SATURDAY...THEN COOLING TEMPERATURES AND PRECIPITATION
CHANCES THROUGH THE FIRST HALF OF NEXT WEEK.

BETWEEN NOW AND SATURDAY...THE UPPER LEVEL TROUGH OVER THE WEST
COAST WILL TRANSITION EAST CENTERED OVER THE SOUTHERN ROCKY
MOUNTAINS. A SURFACE TROUGH WHICH WILL DEVELOP ON THE LEE-SIDE OF
THE ROCKIES PRIOR TO THIS TIME PERIOD WILL STAY IN THE REGION
THROUGH SATURDAY. AS THE UPPER LEVEL TROUGH GETS CLOSER...MODELS
ARE INDICATING A SURFACE LOW STRENGTHENING OVER EASTERN
COLORADO/NORTHWEST KANSAS ON SATURDAY AFTERNOON...WITH AN INVERTED
TROUGH EXTENDING NORTH ACROSS WESTERN NEBRASKA...AND A DRYLINE
GOING SOUTH INTO TEXAS. AHEAD OF THE SURFACE SYSTEM...SOUTHERLY
LOW LEVEL WINDS WILL BRING MOISTURE INTO NEBRASKA. DETERMINISTIC
MODELS ARE VERY ROBUST...BRINGING DEWPOINTS IN THE MID AND UPPER
60S TO MUCH OF THE FORECAST AREA BY SATURDAY AFTERNOON. WAS A BIT
MORE CONSERVATIVE WITH THE FORECAST AND HAVE NEAR 60 TO THE MID
60S ACROSS THE AREA. THIS WILL NEED TO BE WATCHED OVER THE NEXT
DAY TO SEE HOW EFFICIENTLY THIS MOISTURE IS BEING BROUGHT
NORTHWARD. EVEN WITH THE MORE CONSERVATIVE APPROACH...HUMIDITY
WILL BE AT LEVELS MUCH OF THIS AREA HASN/T EXPERIENCED FOR A
WHILE. THIS MOISTURE WILL HELP TO CREATE STRONG INSTABILITY OF 2K-
4K J/KG ACROSS WESTERN AND NORTH CENTRAL NEBRASKA DURING THE
AFTERNOON. DEEP LAYER SHEAR IS LOOKING TO BE SUFFICIENT FOR
ORGANIZED STORMS SO CONTINUE TO LOOK AT SATURDAY AFTERNOON AND
EVENING FOR FIRST FAIRLY WIDESPREAD SEVERE EVENT OF THE YEAR
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. THERE IS A QUESTION TO
HOW MUCH OF THE AREA WILL BE CAPPED THROUGH THE AFTERNOON.
THOUGHTS ARE THAT MUCH OF THE AREA WILL STAY CAPPED THROUGH MID
AFTERNOON...BUT AS THE UPPER LEVEL TROUGH MOVES CLOSER...IT WILL
BE EJECTING SEVERAL WEAK SHORTWAVES THAT WILL BRING ENOUGH LIFT
INTO THE AREA TO TRIGGER STORMS. FORECAST MODELS ARE TRENDING THIS
DIRECTION...WITH CONVECTION BEGINNING AFTER 21Z AND INCREASING
ACROSS THE AREA OVERNIGHT. AFTER 06Z...THE LOW LEVEL JET VEERS TO
THE EAST...SO BELIEVE ANY THREAT FOR SEVERE STORMS WILL END BY
THIS POINT LOCALLY. AND ALTHOUGH MOISTURE TRANSPORT INTO THE LOCAL
AREA ISN/T PARTICULARLY IMPRESSIVE...THE ORIENTATION AND FOCUS IS
AN EXTRA POSITIVE POINT TO GETTING CONVERGENCE AND CONVECTION OVER
THE FORECAST AREA. LARGE HAIL AND DAMAGING WINDS LOOK TO BE THE
PRIMARY SEVERE THREATS...HOWEVER WITH THE SURFACE LOW JUST TO THE
SOUTHWEST OF THE FORECAST AREA...THERE IS SOME CONCERN FOR
TORNADOS...MAINLY ACROSS SOUTHWEST NEBRASKA LATE AFTERNOON/EARLY
EVENING SATURDAY AS MANY PARAMETERS WOULD SUGGEST THIS IS A VALID
THREAT TO PAY ATTENTION TO.

ONE CAVEAT TO THE FORECAST FOR SATURDAY WILL BE STRATUS/FOG
POTENTIAL. THE NAM IS INDICATING A GOOD LAYER OF LOW LEVEL
MOISTURE...WHICH IN PARTS OF THE FORECAST AREA DON/T SCOUR OUT
UNTIL MID AFTERNOON. THIS WOULD LIMIT THE INSTABILITY AND POSSIBLY
THE CHANCES FOR STORMS.

DID ADJUST TEMPERATURES DOWN A FEW DEGREES DUE TO THE STRATUS
EXPECTED IN THE MORNING. HOWEVER...EVEN WITH A SHORT AMOUNT OF
TIME WITH SUN...TEMPERATURES WILL LIKELY RISE QUICKLY SO DIDN/T
LOWER HIGHS BY TOO MUCH.

FOR SUNDAY AND BEYOND...THE UPPER LEVEL TROUGH WILL PULL TO THE
NORTHEAST...AND ACROSS THE CENTRAL PLAINS. THIS WILL KEEP SHOWER
AND THUNDERSTORM CHANCES ACROSS THE AREA FOR SUNDAY. AS THIS
OCCURS...AN UPPER LEVEL LOW WILL FORM OVER THE NORTHERN
PLAINS...WHICH WILL STAY FAIRLY STATIONARY...OR WILL SLOWLY ROTATE
AROUND THE NORTHERN AND CENTRAL PLAINS THROUGH THE FIRST HALF OF
THE WEEK. THE PRESENCE OF THIS SYSTEM OVER THE AREA WILL KEEP
CHANCES FOR RAIN ACROSS MUCH OF THE FORECAST AREA THROUGH THIS
TIME-FRAME. CURRENT INDICATIONS WOULD BE THAT THE HIGHER AMOUNTS
AND MORE WIDESPREAD ACTIVITY WILL BE OVER THE NORTHERN HALF OF
NEBRASKA. ALTHOUGH DON/T ANTICIPATE A LOT OF THUNDERSTORMS WITH
THIS SYSTEM...COLD AIR ALOFT /NEAR 5C AT 850MB/ WILL KEEP LAPSE
RATES IN THE MID LEVELS STEEP TO KEEP AT LEAST MENTION OF ISOLATED
THUNDER MANY OF THESE DAYS. IN ADDITION...TEMPERATURES WILL BE
QUITE A BIT LOWER /AND BELOW NORMAL/ AS THIS SYSTEM PULLS DOWN
COOLER AIR. SO...HAVE TEMPERATURES IN THE 50S TO LOW 70S FOR HIGHS
AND LOWS IN THE UPPER 30S AND 40S FOR THE FIRST PART OF THE WEEK.

BY THE END OF THE WEEK...THE MODELS ARE SHOWING THE UPPER LOW
PUSHING OFF TO THE EAST WHILE ANOTHER STRONG LONGWAVE TROUGH MOVES
INTO THE WEST COAST. THIS WOULD BRING A NARROW...BUT STRONG RIDGE
INTO THE CENTRAL PLAINS. DID START TO BUMP UP HIGH TEMPERATURES A
BIT...AND IF THE MODELS CONTINUE TO SHOW THIS PATTERN WOULD
EXPECT THE UPWARD TREND IN TEMPERATURES TO CONTINUE AS WELL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 626 AM CDT FRI MAY 17 2013

LIFR CEILINGS AT KVTN SHOULD LIFT QUICKLY BY 13Z. VFR CONDITIONS
TO PREVAIL TODAY WITH SOUTH WINDS TO INCREASE LATE MORNING TO
14G22KT THROUGH THIS AFTERNOON. SOUTHEAST WINDS TONIGHT 10-15KT.
STRATUS IS LIKELY TO MOVE NORTH INTO WESTERN NEBRASKA AFTER
MIDNIGHT...SO HAVE INCLUDED AN IFR CEILING OF OVC005 FOR KLBF AFTER
10Z/18TH.

&&

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

$$

SHORT TERM...ROBERG
LONG TERM...BROOKS
AVIATION...ROBERG