Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 122348
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
648 PM CDT SAT JUL 12 2014

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 431 PM CDT SAT JUL 12 2014

THE MAIN ISSUE DURING THE NEXT 24 HOURS INVOLVES HOW MUCH (OR MORE
LIKELY FOR MANY AREAS HOW LITTLE) OF A RISK FOR
SHOWERS/THUNDERSTORMS EXISTS...AND WHETHER OR NOT AN OUTSIDE
CHANCE OF STRONG TO POTENTIALLY SEVERE STORMS MIGHT STILL BE IN
PLAY FOR MAINLY THE 5PM-MIDNIGHT TIME FRAME...AND MAINLY WITHIN
THE SOUTHEAST 1/3 OF THE CWA. OTHERWISE...ONE MORE SEASONABLY WARM
DAY IS ANTICIPATED FOR SUNDAY BEFORE THE WELL-ADVERTISED COOL-DOWN
GETS UNDERWAY FOR THE EARLY-MIDDLE PART OF NEXT WEEK AS COVERED IN
THE LONG-TERM BELOW.

STARTING WITH THE HERE AND NOW AS OF 20Z/3PM...RADAR SHOWS
ESSENTIALLY A CLEAN SLATE NOT ONLY WITHIN BUT ALSO NEARBY THE
CWA...AS THE NEAREST ORGANIZED SHOWER ACTIVITY IS WELL NORTHEAST
INTO NORTHERN IA. IN OTHER WORDS...EARLIER MODEL RUNS ESPECIALLY
FROM MODELS SUCH AS THE NAM HAVE PROVEN GROSSLY OVERDONE WITH
AFTERNOON SHOWER/STORM DEVELOPMENT THUS FAR. PER WATER VAPOR
IMAGERY AND SHORT TERM MODEL DATA...THE BIG PICTURE IN THE MID-
UPPER LEVELS INVOLVES CONTINUED MODESTLY STRONG QUASI-ZONAL FLOW
OVER THE LOCAL AREAS...WITH THE AREA GENERALLY SANDWICHED BETWEEN
THE PRIMARY FEATURES OF A SUBTROPICAL RIDGE CENTERED FROM NV/UT
EASTWARD INTO SOUTHERN KS/OK...AND AN INCREASINGLY-WELL DEFINED
LARGER SCALE TROUGH CURRENTLY FROM THE EASTERN HALF OF CANADA INTO
THE NORTHEAST CONUS. THE PRIMARY/NOTABLY DEEP CLOSED LOW
ASSOCIATED WITH THIS TROUGH IS STILL WELL UP INTO CANADA TO THE
WEST OF HUDSON BAY. AT THE SURFACE...THE FIRST IN A SERIES OF COLD
FRONTS OVER THE NEXT FEW DAYS IS ACTUALLY VERY WELL-DEFINED AT
THIS HOUR ACROSS THE SOUTHERN CWA...SLICING ALONG ROUGHLY A
PHILLIPSBURG-HEBRON LINE. FOR MOST AREAS NORTH OF THIS
LINE...SKIES HAVE RANGED FROM PARTLY TO MOSTLY CLOUDY TODAY AS
STEADY NORTH BREEZES GENERALLY 10-15 MPH WITH SOME HIGHER GUSTS
HAVE WORKED IN BEHIND THE BOUNDARY...WHILE TO THE SOUTH BREEZES
HAVE TRANSITIONED FROM SOUTHERLY TO WESTERLY UNDER SUNNY-MOSTLY
SUNNY SKIES. NEEDLESS TO SAY...A VERY IMPRESSIVE TEMPERATURE
GRADIENT FOR THIS TIME OF YEAR SET UP TODAY THANKS TO THE PRESENCE
OF THIS FRONT AND VARIATION IN CLOUD COVER...AS HIGHS APPEAR ON
TRACK TO RANGE FROM ONLY THE MID-UPPER 70S FAR NORTH TO THE MID-
UPPER 90S SOUTH. A FEW OF THESE SOUTHERN LOCATIONS ARE OBSERVING
HEAT INDEX VALUES RIGHT UP TO AROUND 100 DEGREES...BUT STILL
SAFELY BELOW ADVISORY CRITERIA OF 105.

LOOKING FORWARD THROUGH LATE THIS AFTERNOON INTO TONIGHT...THE
MOST BASIC CHANGE FROM THE PREVIOUS EARLY-MORNING FORECAST IS THAT
POPS HAVE BEEN LOWERED AND/OR REMOVED ACROSS THE MAJORITY OF THE
CWA...BUT HAVE ACTUALLY BEEN RAISED A TOUCH IN SOUTHEAST ZONES
MAINLY FOR THE POST-SUNSET HOURS TONIGHT. HOWEVER...GIVEN LOW
CONFIDENCE IN HOW THINGS PLAY OUT HAVE KEPT POPS NO HIGHER THAN
40-50 PERCENT EVEN IN THESE FAR SOUTHERN/SOUTHEAST ZONES. AS FOR
THE BIG MID-UPPER LEVEL PICTURE...THE MAIN PLAYER THROUGH TONIGHT
LOCALLY WILL THE GLANCING BLOW OF A LOW-AMPLITUDE SHORTWAVE TROUGH
THAT IS PRIMARILY PASSING ACROSS IA/MN AND POINTS EAST...AND WELL
TO THE SOUTH OF THE MORE NOTABLE/LARGER CLOSED LOW SLOWLY DROPPING
SOUTH-SOUTHEAST OUT OF CANADA TOWARD THE GREAT LAKES. MEANWHILE AT
THE SURFACE LOCALLY...THE COLD FRONT WILL HAVE PASSED THROUGH THE
ENTIRE CWA BY EARLY THIS EVENING...WITH GENERALLY LIGHT NORTHERLY
WINDS OF NO MORE THAN 5-10 MPH DEFINING MOST OF THE NIGHT-TIME
HOURS. THE MAIN QUESTION CONTINUES TO BE WHETHER OR NOT LEGITIMATE
SHOWER/STORM ACTIVITY WILL EVENTUALLY DEVELOP WITHIN THE CWA. PER
THE LATEST SHORTER TERM/HIGHER-RES SOLUTION OF MODELS SUCH AS THE
RAP/HRRR/4KM WRF-NMM...ITS LOOKING INCREASINGLY UNLIKELY THAT
AREAS GENERALLY NORTH OF AN ALMA-FAIRMONT LINE (ROUGHLY THE
NORTHWEST TWO-THIRDS OF THE CWA) WILL SEE ANYTHING...AND HAVE ONLY
KEPT SOME SLIGHT 20 POPS NORTH OF THIS LINE INTO THIS EVENING
WHILE GRADUALLY ENDING THEM ALTOGETHER FROM NORTH-TO-SOUTH.
MEANWHILE...HAVE LEFT SOME MODEST (BUT BELOW LIKELY) POPS SOUTH OF
THE AFOREMENTIONED LINE...PRIMARILY TO ACCOUNT FOR TWO
POSSIBILITIES. ONE IS THE OUTSIDE CHANCE THAT A FEW DAYLIGHT
STORMS COULD STILL FIRE UP ALONG/NEAR THE COLD FRONT IN AN
ENVIRONMENT CHARACTERIZED BY UP TO AROUND 1500 J/KG MLCAPE AND
ONLY MODEST DEEP LAYER SHEAR AROUND 30KT. HOWEVER...VISIBLE
SATELLITE CONFIRMS THAT AT LEAST SLIGHT CAPPING STILL REMAINS
WHICH IS NOT SURPRISING GIVEN WARM MID LEVEL TEMPS OF AROUND +12C
EVIDENT AT 700MB...SO THIS DAYTIME DEVELOPMENT IS UNCLEAR. THE
SECOND POSSIBILITY FOR HIGHER PRECIP CHANCES IN SOUTHEAST ZONES
COMES LATER THIS EVENING/OVERNIGHT...AS A MODEST INCREASE IN
LARGE-SCALE FORCING INCLUDING FAIRLY EVIDENT MID-LEVEL
CONVERGENCE EVIDENT AT 700 MILLIBARS WORKS SOUTHWARD IN TANDEM
WITH THE TRAILING EDGE OF THE DEPARTING SHORTWAVE
TROUGH...POSSIBLY SPARKING A FLARE-UP OF OVERNIGHT CONVECTION.
DEPENDING ON WHEN THIS OCCURS...WOULD NOT EXPECT MUCH OF SEVERE
THREAT AFTER MIDNIGHT...BUT PRIOR TO THEN CANNOT COMPLETELY RULE
OUT A FEW STRONG TO SEVERE STORMS GIVEN THE ENVIRONMENT...AND WILL
MAINTAIN SOME STRONG TO SEVERE POTENTIAL IN THE HAZARDOUS WEATHER
OUTLOOK AT LEAST FOR NOW. TEMP-WISE...MADE LITTLE TO CHANGE TO
OVERNIGHT LOWS...AIMING FOR LOW-MID 60S NORTH TO UPPER 60S/NEAR-70
SOUTH.

FOR THE DAYTIME HOURS SUNDAY...CONFIDENCE IS REASONABLY HIGH THAT
THE MAJORITY OF THE CWA REMAINS DRY THE MAJORITY OF THE DAY.
HOWEVER GIVEN THAT THE PREVIOUS FORECAST ALREADY HAD SOME SLIGHT
POPS IN MOST AREAS AT SOME POINT DURING THE DAY...AND THAT SOME
MODELS STILL SUGGEST A SMATTERING OF MAINLY AFTERNOON SHOWERS AND
LIKELY WEAK THUNDERSTORMS ASSOCIATED WITH THE LEADING EDGES OF THE
NEXT INCOMING COLD FRONT AND MORE IMPORTANTLY COOLER/LESS-CAPPED
AIR ALOFT...WILL KEEP A SLIGHT CHANCE OF SHOWERS/STORMS
GOING...ESPECIALLY FOR THE AFTERNOON HOURS. IN THE MID-UPPER
LEVELS...HEIGHTS CONTINUE A SLOW FALL LOCALLY ALONG THE
SOUTHWESTER PERIPHERY OF THE TROUGH ASSOCIATED WITH THE VERY DEEP
CANADIAN LOW GETS AS IT GETS CLOSER TO LAKE SUPERIOR BY LATE IN
THE DAY. AS A RESULT...DAYTIME HEATING COULD EASILY KICK UP AT
LEAST ISOLATED CONVECTION GIVEN MLCAPE FORECAST TO CLIMB INTO THE
500-1000 J/KG RANGE ACROSS MUCH OF THE CWA PER THE 18Z GFS.
ALTHOUGH NOT EXPECTING ANY LEGITIMATE SEVERE WEATHER
THREAT...SUPPOSE SOME SMALL HAIL IS NOT OUT OF THE QUESTION IF
THIS DEVELOPMENT DOES TAKE PLACE...ESPECIALLY GIVEN UP TO AROUND
40KT OF DEEP-LAYER SHEAR DURING THE MID-LATE AFTERNOON. TEMP-
WISE...ASSUMING THAT THERE ARE NO UNEXPECTED PROLONGED PERIODS OF
MOSTLY CLOUDY SKIES...TEMPS SHOULD STILL WARM TO SEASONABLE
LEVELS...AND AGAIN MADE ONLY MINOR TWEAKS AIMING MOST NEB ZONES
INTO THE MID-80S AND MORE SO UPPER-80S TO NEAR 90 ALONG AND SOUTH
OF THE STATE LINE. BREEZES SHOULD GENERALLY AVERAGE AROUND 10 MPH
MAINLY FROM A NORTHERLY DIRECTION.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 431 PM CDT SAT JUL 12 2014

THE BIG STORY WILL BE THE UNSEASONABLY COOL AIRMASS THAT WILL BEGIN
TO MOVE INTO THE AREA MONDAY AND COULD RESULT IN NEAR RECORD COOL
HIGHS AND LOWS BY TUESDAY. MODERATION WILL BE GRADUAL WITH BELOW
NORMAL TEMPERATURES EXPECTED THROUGH AT LEAST FRIDAY. THERE ARE SOME
LOW END CHANCES OF SHOWERS AND NON SEVERE THUNDERSTORMS PRIMARILY
ACROSS SOUTHWESTERN AND SOUTHERN ZONES.

SUNDAY NIGHT...SEVERAL FORECAST MODELS ARE INDICATING A VERY SLIGHT
CHANCE OF A FEW LIGHT RAIN SHOWERS OR WEAK THUNDERSTORMS IN
ASSOCIATION WITH THE LEADING EDGE OF THE UPPER VORT MAX THAT WILL BE
TRACKING SOUTH INTO THE GREAT LAKES. THIS SYSTEM WILL FORCE A COOL
FRONT INTO OUR CWA WITH FALLING HEIGHT FIELDS AS WE NEAR DAWN MONDAY
MORNING.

MONDAY...COOL AIR ADVECTION ALOFT IS EXPECTED THROUGHOUT THE DAY
WHICH WILL RESULT IN AFTERNOON HIGHS THAT SHOULD BE AROUND 10
DEGREES COOLER THAN ON SUNDAY. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE WITH THE INITIAL PUSH OF COOLER AIR PRIMARILY DURING THE
MORNING WITH DECREASING CHANCES OF PRECIPITATION AS WE HEAD THROUGH
THE DAY. OVERALL PRECIPITATION CHANCES ARE LOW AND FAVOR SOUTHERN
ZONES. INSTABILITY IS WEAK AND THUS SEVERE WEATHER IS NOT EXPECTED.

TUESDAY...THIS WILL LIKELY BE THE COOLEST DAY OF THE WEEK AND THIS
AIRMASS IS COMING FROM THE HUDSON BAY REGION AND THUS IT IS VERY
ABNORMALLY COOL FOR THIS TIME OF YEAR. IN FACT...WE ARE CURRENTLY
FORECASTING NEAR RECORD LOWS AND NEAR RECORD LOW HIGHS ON TUESDAY.
THE RECORD LOW AND LOW HIGH IN GRAND ON TUESDAY IS 48 AND 72F. THE
RECORD LOW AND LOW HIGH IN HASTINGS ON TUESDAY IS 52 AND 67F. FOR
BOTH CITIES WE ARE FORECASTING A TUESDAY MORNING LOW OF 52 AND A
HIGH AROUND 73F...SO WE WILL CERTAINLY BE RIGHT AROUND THOSE RECORD
LOW VALUES.

TUESDAY NIGHT INTO WEDNESDAY...AN UPPER LEVEL VORT MAX WILL SLIDE
SOUTHEAST DOWN THE FRONT RANGE WITH UPSLOPE SFC FLOW. THE BEST
CHANCE OF SHOWERS OR WEAK THUNDERSTORMS WILL BE TO THE WEST OF OUR
CWA...BUT OUR SOUTHWESTERN ZONES WILL SEE AT LEAST SOME CHANCE OF
PRECIPITATION WITH THIS UPPER FEATURE. MODERATION ON WEDNESDAY WILL
BE RATHER MINOR WITH HIGHS STILL IN THE 70S.

THURSDAY THROUGH SATURDAY...THE UPPER FLOW WILL BECOME A LITTLE MORE
QUASI-ZONAL AND OUR AIRMASS WILL CONTINUE TO MODERATE WITH HIGHS
BACK INTO THE MID 80S BY FRIDAY AND AROUND NORMAL ON
SATURDAY...WHICH IS GENERALLY UPPER 80S NEBRASKA TO AROUND 90 OVER
NORTHERN KANSAS. THIS CURRENTLY APPEARS TO BE A DRY PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 646 PM CDT SAT JUL 12 2014

THUNDESTORMS HAVE DEVELOPED ALONG A COLD FRONTAL BOUNDARY SOUTH OF
THE TERMINALS AND CONVECTION IS NOT EXPECTED FOR KGRI AND KEAR
THROUGH THE NIGHT TIME HOURS. NORTHERLY WINDS WILL GRADUALLY
TRANSITION NORTHWEST AND WEST DURING THE TAF PERIOD. CONFIDENCE IS
NOT HIGH IN THE POTENTIAL FOR MVFR TOWARD IFR CONDITIONS BUT DID
KEEP A MENTION OF THE POSSIBILITY FOR A LOWER CIG OR VSBY. HIT OR
MISS CHCS FOR STORMS EXIST ON SUNDAY AND JUST CARRIED A VCTS.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.

&&

$$

SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...FAY


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