Area Forecast Discussion Issued by NWS Hastings, NE
000
FXUS63 KGID 141113
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
613 AM CDT TUE MAY 14 2013
.UPDATE...
ISSUED AT 613 AM CDT TUE MAY 14 2013
NO SUBSTANTIAL CHANGES THRU 14Z. DID MAKE SOME CHANGES TO THE
WINDS 15-18Z AS THERE SHOULD BE A PERIOD OF BREEZY CONDITIONS ALL
AREAS AS WHAT IS LEFT OF THE DIMINISHING LLJ MIXES DOWN DURING THE
INITIAL COUPLING OF THE SFC LAYER TO THE EML. THEN GUSTINESS WILL
ENDS N AND W OF THE TRI-CITIES AFTER 18Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 430 AM CDT TUE MAY 14 2013
ALOFT: THE LONG-WAVE /LGWV/ FLOW WAS TRANSITIONING FROM A WRN RIDGE/
ERN TROF TO ZONAL FLOW DUE TO A POTENT SHORT-WAVE TROF ADVANCING E
ALONG THE US-CAN BORDER. IR SATELLITE SHOWS AN UPR-LVL HIGH OVERHEAD
AT THIS TIME. THIS HIGH WILL ALSO SLIP E AND FADE AWAY WHILE RAISING
HGTS OVER THE ERN USA. THE CUT-OFF LOW OVER THE GULF OF CA WILL
BECOME MOBILE TODAY AND REACH W TX TNGT. THIS LOW WILL NOT PLAY A
ROLE IN OUR WX HERE.
SFC: LOW PRES WILL ACCOMPANY THE TROF ALONG THE US-CAN BORDER. ITS
ASSOCIATED COOL FRONT WILL MOVE EASE INTO NEB DURING PEAK HEATING
THIS AFTN AND THEN INTO NRN KS AFTER DARK.
THRU SUNRISE: M/CLEAR WITH PATCHES OF MOSTLY THIN CIRRUS.
TODAY: SUNNY AND HOT WITH NEAR RECORD HIGHS /93-99F/. THOSE
LOCATIONS THAT DIDN/T HIT THE FIRST 90F OF THE YEAR YESTERDAY
/BASICALLY ALONG AND E OF HWY 281/ WILL DO IT TODAY.
+26C H8 TEMPS POKE IN HERE WHICH IS 3 STANDARD DEVIATIONS ABOVE
NORMAL FOR THE MIDDLE OF MAY. TO PUT THIS IN PERSPECTIVE...GRI HAS
ONLY BEEN 95F OR HOTTER ONE OTHER TIME ON MAY 14TH /118 YRS OF
RECORDS/. H5 HGTS WERE 584 ON THE 00Z LBF SOUNDING. THIS IS 20M
HIGHER THAN MODELED THE LAST COUPLE DAYS.
HAVE FCST HIGHS JUST SHORT OF RECORDS AT GRI AND HSI:
GRI 99 IN 1941
HSI 97 IN 1941
WE CONTINUE TO SEE A SIGNAL FOR A FEW ISOLATED HIGH-BASED TSTMS
AFTER 4 PM IN THE HI-RES MODELS WITH EXPLICIT CONVECTION. VERTICAL
CROSS SECTION SHOWS SIGNIFICANT LIFT AS THE UPWARD BRANCH OF THE
FRONTOGENETICAL CIRCULATION MOVES IN WITH THE FRONT. THE SUBSIDENT
BRANCH WILL KEEP N-CNTRL KS CAPPED. THERE IS NO QG FORCING SO THE
FGEN LIFT IS ON ITS OWN. THAT COMBINED WITH VERY DRY LOW-LVLS WILL
KEEP TSTM DEVELOPMENT FAIRLY LIMITED.
THE INVERTED V FCST SOUNDINGS SUGGEST ANY STORMS THAT DEVELOP IN
THIS ENVIRONMENT COULD PRODUCE LOCALLY DAMAGING MICROBURST WINDS.
NAM DCAPE PRIOR TO CONVECTIVE INITIATION IS FCST AROUND 2000 J/KG.
WINDS IN THE CLOUD-BEARING LAYER /3-6 KM/ WILL AVERAGE 10-20 KTS BUT
SHEAR WILL ONLY BE 5-10 KTS. SO ANY TSTMS WILL BE PULSE IN NATURE.
PLEASE SEE FIRE WX SECTION REGARDING CONVERSION OF PART OF THE FIRE
WX WATCH TO A RFW.
TNGT: P/CLOUDY. TSTMS PROBABLY LINGER INTO THE EVNG HRS AND DIMINISH
WITH LOSS OF HEATING. THE DEPTH OF THE FGEN CIRCULATION IS FCST TO
DIMINISH BELOW 2 KM BY 03Z AND THIS IS PROBABLY NOT ENUF TO FORCE
PARCELS TO THE LFC.
IF TSTMS LINGER MUCH PAST 9 PM...HAVE TO WONDER IF AN ISOLATED
HEATBURST IS POSSIBLE AS THEY DISSIPATE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 430 AM CDT TUE MAY 14 2013
OVERALL THIS WILL BE A FAIRLY ACTIVE WEATHER PERIOD WITH NUMEROUS
CHANCES FOR SHOWERS AND THUNDERSTORMS. IT WILL ALSO BE WARM WITH
TEMPERATURES GENERALLY RUNNING ABOVE NORMAL.
WEDNESDAY...THE COLD FRONT WILL HAVE PRESSED SOUTH INTO NORTHERN
KANSAS RESULTING IN A 10F TO 20F DROP IN HIGH TEMPERATURES FROM THE
NEAR RECORD WARMTH OF TUESDAY. A COOLER EAST NORTHEAST WIND AT
AROUND 15 MPH WILL HELP LOWER HIGHS BACK INTO THE UPPER 70S TO LOWER
80S. IT SHOULD BE A DRY DAY FOR MOST LOCATIONS...BUT WILL KEEP A
VERY SLIGHT CHANCE OF THUNDERSTORMS IN THE FORECAST THROUGH
WEDNESDAY NIGHT ACROSS OUR SOUTHERN MOST KANSAS COUNTIES THAT WILL
BE IN THE VICINITY OF THE SFC COLD FRONT.
THURSDAY...THE FRONT WILL LIFT BACK NORTH THROUGH NEBRASKA AS A WARM
FRONT. IN ADDITION...A WEAK 500MB SHORT WAVE WILL TRACK ACROSS THE
CENTRAL PLAINS. THIS WILL RESULT IN AN INCREASING CHANCE OF SHOWERS
AND THUNDERSTORMS AS WE HEAD THROUGH THE DAY. UPPER LEVEL WINDS ARE
ABNORMALLY WEAK FOR THIS TIME OF YEAR AND THUS THERE IS VERY LITTLE
WIND SHEAR. THERE IS SOME WEAK INSTABILITY...BUT GIVEN THE LACK OF
SHEAR...SEVERE WEATHER SEEMS UNLIKELY OR VERY ISOLATED. TEMPERATURES
WILL NOT WARM TOO MUCH GIVEN INCREASING CLOUDS...BUT STILL EXPECT
ABOVE NORMAL HIGHS GENERALLY AROUND 80F. THE CHANCE OF THUNDERSTORMS
WILL CONTINUE INTO THURSDAY NIGHT.
FRIDAY...MOST OF THE DAY SHOULD BE DRY...BUT WILL CONTINUE TO CARRY
A CHANCE OF THUNDERSTORMS FOR PRIMARILY THE AFTERNOON/EVENING HOURS
WITH STRONG DIURNAL HEATING AND ANOTHER WEAK VORT MAX IN THE AREA.
THE MAIN UPPER TROUGH WITH THE BEST DYNAMICS AND UPPER LEVEL SUPPORT
WILL STILL BE LOCATED OVER THE ROCKIES...WELL WEST OF OUR FORECAST
AREA. THEREFORE...THE WIND SHEAR WILL CONTINUE TO BE WEAK AND SEVERE
WEATHER IS UNLIKELY OR WILL BE RATHER ISOLATED. THUNDERSTORMS MAY
ROLL INTO OUR AREA FROM THE WEST DURING THE LATE AFTERNOON AND
EVENING HOURS.
SATURDAY/SATURDAY NIGHT...THIS CONTINUES TO LOOK LIKE OUR BEST SHOT
AT STRONG TO SEVERE THUNDERSTORMS AS THE UPPER TROUGH WILL PUSH INTO
THE CENTRAL PLAINS. THIS WILL USHER IN STRONGER WINDS ALOFT AND A NICE
INCREASE IN WIND SHEAR. INSTABILITY WILL ALSO INCREASE ACCORDING TO
MOST MODELS AND ML CAPE VALUES COULD BE AROUND 2000-3000 J/KG. THE
COMBINATION OF WIND SHEAR AND INSTABILITY APPEARS FAVORABLE FOR
SEVERE WEATHER ACROSS PORTIONS OF OUR FORECAST AREA. THIS IS STILL
SEVERAL DAYS AWAY AND THE DETAILS ON WHEN AND WHERE SEVERE
THUNDERSTORMS WILL BE MOST LIKELY WILL DEPEND ON THE TIMING OF THE
UPPER WAVE...WHICH SHOULD COME INTO BETTER FOCUS IN THE COMING DAYS.
AT THIS TIME WE APPEAR TO BE IN THE WARM MOIST SECTOR FOR A MAJORITY
OF THE DAY AND THUS HIGHS SHOULD CONTINUE TO RUN ABOVE NORMAL IN THE
80S.
SUNDAY AND MONDAY...TEMPERATURES WILL COOL BACK INTO THE 70S AS THE
UPPER WAVE KICKS THROUGH AND SFC WINDS BECOME NORTHWESTERLY. A FEW
LINGERING SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE WITH THE FOCUS
ACROSS OUR SOUTHEASTERN ZONES AS VORT MAXES ROTATE THROUGH.
HOWEVER...OUR DEWPOINTS WILL HAVE FALLEN AND PRECIPITATION CHANCES
WILL ALSO BE LOWER AND MORE IN THE SLIGHT CHANCE CATEGORY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 613 AM CDT TUE MAY 14 2013
TUE: VFR. THERE IS A VERY LOW PROB FOR A TSTM AFTER 21Z. IF A TSTM
HAPPENS TO DEVELOP INVOF THE TERMINAL...THERE IS A RISK OF 50 KT
MICROBURST WINDS AND SVR WIND SHEAR. SSW WINDS AVERAGE 15 KTS WITH
A PERIOD OF GUSTS 21-24 KTS ROUGHLY 15Z-18Z.
TNGT: VFR. VERY LOW PROB FOR A TSTM ENDS...PROBABLY BY 05Z. WINDS
DECREASE AND MAY BECOME LGT AND VARIABLE UNTIL A COOL FRONT MOVES
THRU AROUND 01Z...SHIFTING WINDS TO NE.
CIGS CONFIDENCE: HIGH
VSBY CONFIDENCE: HIGH
WIND CONFIDENCE: HIGH
WX CONFIDENCE: HIGH
&&
.FIRE WEATHER...
ISSUED AT 430 AM CDT TUE MAY 14 2013
AFTER COORDINATION WITH LBF/OAX THE FIRE WX WATCH HAS BEEN
CANCELLED FOR MOST OF OUR S-CNTRL NEB COUNTIES. THERE WAS GOOD
AGREEMENT THAT PRES GRADIENT JUST WONT SUPPORT WINDS REACHING
WARNING CRITERIA. HOWEVER THE WATCH WAS UPGRADED TO A WARNING
ALONG HWY 81 /POLK-THAYER COUNTIES/ AND NUCKOLLS AND CLAY
COUNTIES. THE PRES GRADIENT WILL BE STRONG ENUF FOR 3 HRS OF
FREQUENT GUSTS 25-30 MPH AND POSSIBLE AN HOUR OR TWO OF SUSTAINED
WINDS OF 20 MPH.
HOWEVER...OUTSIDE OF THE RFW AREA ISOLATED TSTMS WILL HAVE THE
POTENTIAL TO PRODUCE LOCALLY STRONG WIND GUSTS.
WHILE OUR N-CNTRL KS COUNTIES WILL BE VERY DRY WITH GUSTY WINDS
...FUEL STATUS PRECLUDED A RFW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING FROM 11 AM THIS MORNING TO 9 PM CDT THIS
EVENING FOR NEZ049-064-076-077-086-087.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...WESELY
AVIATION...HALBLAUB
FIRE WEATHER...HALBLAUB