Area Forecast Discussion
Issued by NWS Hastings, NE

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000
FXUS63 KGID 220838
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
338 AM CDT FRI AUG 22 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT FRI AUG 22 2014

FOCUS IS THUNDERSTORM AND SEVERE WEATHER POTENTIAL.

THE PATTERN ALOFT WAS DOMINATED BY A RIDGE IN THE NORTHERN
PACIFIC...A TROUGH ALONG THE WEST COAST AND RIDGING FROM THE GULF
COAST TO THE GREAT LAKES REGION.  AT THE SURFACE...LOW PRESSURE WAS
ORIENTED FROM NORTHEAST NM TO SOUTHERN MN...AND THE SFC TROUGH/WARM
FRONTAL BOUNDARY WAS ACTIVE FOR CONVECTION DURING THE EVENING
HOURS.

AS WE HEAD THROUGH THE DAY TODAY...THE SURFACE LOW WILL DEEPEN AND
LIFT NORTH ACROSS WESTERN KANSAS WITH THE WARM FRONTAL BOUNDARY
ORIENTING NEAR THE KS/NEB STATELINE TOWARD EVENING.  THE FRONTAL
BOUNDARY COMBINED WITH A DECENT WAVE AS SEEN ON WV IMAGERY IN
AZ...WILL LIFT NORTHEAST AHEAD OF THE MEAN UPPER TROUGH IN THE
PACIFIC NORTHWEST AND AID IN INITIATING ANOTHER ROUND OF
CONVECTION LATER TODAY/TONIGHT. HIGH INSTABILITY WILL EXIST ALONG
AND NORTH OF THE FRONT WITH 4000 J/KG EXPECTED FM THE NEB/KS
STATELINE NORTHWARD INTO SOUTHERN NEB. SHEAR PARAMETERS IN GENERAL
AVERAGE 30KTS BUT INCREASE OVER 30KTS ACROSS OUR WESTERN ZONES IN
CLOSER PROXIMITY TO THE SURFACE LOW. MODELS SUGGEST THE BRUNT OF
THE CONVECTION WILL BE ACROSS WESTERN NEBRASKA AND KANSAS...BUT
THE FRONTAL BOUNDARY HAS BEEN ACTIVE THE LAST COUPLE OF DAYS AND
BELIEVE THIS WILL BE THE CASE TODAY. WITH THE HIGH
INSTABILITY...GOOD SHEAR AND BOUNDARY IN PLACE...CONDITIONS WILL
BE FAVORABLE FOR SEVERE THUNDERSTORMS WITH LARGE HAIL OF GOLF BALL
SIZE OR GREATER POSSIBLE AND DAMAGING TSTM WIND GUSTS. CANNOT RULE
OUT THE POTENTIAL FOR A TORNADO ESPECIALLY IN THE VICINITY OF THE
FRONT OR NEAR SFC LOW. HIGH DPS AND PRECIPITABLE WATER VALUES OF
AN IN INCH AND A HALF TO TWO INCHES WILL BRING THE POSSIBILITY OF
VERY HEAVY RAINFALL/LOCALIZED FLOODING ESPECIALLY FOR LOCATIONS
WHICH HAVE RECEIVED DECENT RAINFALL AMOUNTS THE LAST COUPLE OF
DAYS. FFG IS STILL IN THE 2 TO 3 INCH RANGE SO NOT LOOKING FOR A
LOT OF HYDRO ISSUES JUST YET.

AFTERNOON TEMPERATURES WILL BE TOASTY SOUTH OF THE WARM FRONT IN
KANSAS WITH READINGS WELL INTO THE 90S TO AROUND 100F...WHILE TO
THE NORTH OF THE FRONT UPPER 80S TO LOW 90S ARE FORECAST.

THE WARM FRONTAL BOUNDARY WILL LIFT NORTH TONIGHT WITH THE
PROGRESSING UPPER WAVE...AND THE NOSE OF A 40KT LLVL JET ORIENTS
ACROSS NORTHERN AND EASTERN NEB. THE THUNDERSTORMS ARE EXPECTED TO
INCREASE IN COVERAGE ALONG/NORTH OF THE FRONT DURING THE EVENING
BEFORE LIFTING INTO NORTHERN NEB OVERNIGHT.

.LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 320 AM CDT FRI
AUG 22 2014

ALOFT: AMPLIFIED SW FLOW WILL DOMINATE THRU TUE WITH A TROF OVER THE
WRN USA. THE MOST DYNAMIC EMBEDDED SHORTWAVE TROF WILL EJECT ACROSS
THE NRN PLAINS SUN LEAVING A +TILT REMNANT TROF REMAINING IN ITS
WAKE. THIS TROF WILL BECOME PROGRESSIVE AND SLIDE THRU HERE TUE-WED
WITH DEAMPLIFICATION. THE EC/GEM/GFS/UKMET ARE IN GOOD AGREEMENT.

AS FOR THE SHORTER WAVELENGTHS...PLEASE SEE THE 1213 AM MODEL
DIAGNOSTIC DISCUSSION /PMDHMD/ FOR DETAILED MODEL ASSESSMENT. THE
LOW CURRENTLY OVER THE DESERT SW WILL OPEN UP AND LIFT THRU HERE
SAT. THE DIGGING/POTENT LOW OVER THE NRN ROCKIES WILL TAKE ON -TILT
SUN /JUST NW OF THE FCST AREA/ AS AN 80 KT UPPER-LVL JET SWINGS
AROUND ITS BASE. WSW FLOW FOLLOWS MON-TUE WITH THE LAGGING TROF
MOVING THRU LATE TUE. SUBSIDENT NW FLOW MAY MOVE IN WED-THU. THE
12Z/00Z GEM AND NOW THE 00Z EC CUT-OFF A LOW AT THE BASED OF THE
TROF WITH THE WESTERLIES BECOMING RE-ESTABLISHED OVER CANADA.

SURFACE: LOW PRES AND A CONVECTIVELY ACTIVE WARM FRONT WILL BE
LIFTING THRU THE FCST AREA SAT. A WEAK COOL FRONT WILL SLIDE THRU
BEHIND IT SUN. A STRONGER SECONDARY FRONT WILL FOLLOW SUN NIGHT.
THIS FRONT WILL BECOME STATIONARY ALONG THE KS-NEB BORDER MON UNTIL
THE UPPER TROF MOVES THRU...SHOVING THE FRONT DOWN INTO THE SRN
PLAINS TUE. CANADIAN HIGH PRES WILL ARRIVE WED WITH RETURN FLOW
AND A NEW LEE-SIDE TROF DEVELOPING THU.

HAZARDS: MULTIPLE EPISODES OF TSTMS ARE POSSIBLE SAT-TUE. HEAT
BURSTS COULD BE A PROBLEM SAT NIGHT. AS OF NOW THERE ARE NO OBVIOUS
THREATS OF SEVERE TSTMS...BUT THERE CERTAINLY WILL BE POTENTIAL.


THE DAILY DETAILS...

SAT: OVERNIGHT TSTM ACTIVITY SHOULD BE OFF TO THE N BY DAYBREAK.
DOESNT LOOK LIKE MUCH LOW-LVL FORCING TO INITIATE AFTERNOON TSTMS
AND THE LOW-LVL MOIST TONGUE WILL LIFT N WITH THE WARM FRONT. FCST
NAM/EC/GFS SOUNDINGS MINIMAL CAPPING THOUGH. WE MAY ALSO BE TOO HIGH
ON OUR FCST DWPTS BY 5F. FOR NOW HAVE A SLIGHT CHANCE OF A TSTM
AFTER 4 PM. IF TSTMS DEVELOP THEY WILL BE HIGH-BASED AND GUSTY WITH
CONVECTIVE CONDENSATION LVLS AROUND 10K FT.

BREEZY FROM HWY 281 E AS MIXING RESULTS IN DOWNWARD TRANSFER OF THE
LLJ.

SAT NIGHT: STRONG CONVERGENCE AS THE COOL FRONT MOVES IN. AGAIN TSTM
INITIATION IS HIGHLY UNCERTAIN. SO ONLY HAVE A SLIGHT CHANCE POP IN
THE FCST. WITH SKINNY CAPE ABOVE 10K FT AND AN INVERT-V LOOK TO THE
SOUNDINGS...HAVE TO WONDER IF HEAT BURSTS MAY BE A PROBLEM "IF"
TSTMS CAN DEVELOP.

SUN: COOL FRONTAL PASSAGE WITH COOL/DRY AIR ADVECTION. TEMPS DROP
BACK TO NEAR NORMAL. LOOKING VERY NICE AND COMFORTABLE FOR OUTDOOR
ACTIVITIES.

SUN NIGHT: UPSLOPE FLOW COULD RESULT IN TSTMS JUST TO THE W OF THE
FCST AREA. THE FCST COULD BE OVERDONE ON POPS. THE EC/GFS DO NOT
AGREE ON THE LOCATION OF THE FRONT. BELIEVE THE EC/GEM FURTHER S
POSITION IS BEST GIVEN THE STRENGTH OF THE SYSTEM ALOFT.

MON: WEAK LEE CYCLOGENESIS RESULT IN THE FRONT LIFTING BACK N.
SUBSTANTIAL TSTM/MCS ACTIVITY EXPECTED MON NIGHT AS THE LLJ IMPINGES
ON THE FRONT AND WAA/FRONTOGENESIS DEVELOP.

THIS HAS HEAVY RAIN POTENTIAL WRITTEN ON IT. GEM/EC/GFS QPF IS
IMPRESSIVE WITH POCKETS OF 1-3".

TUE: BELOW AVERAGE CONFIDENCE ON TEMPS. THERE COULD BE SUBSTANTIAL
CLOUD COVER UNDERNEATH THE FRONT. CANT RULE OUT MORE TSTM ACTIVITY
INTO TUE NIGHT AS THE STRONGER COOL FRONT MOVES IN.

WED-THU: FAIR AND DRY. HOWEVER...WE ARE CARRYING A SLIGHT CHANCE OF
TSTMS WED. THIS PROBABLY IS OVERDONE. COMFORTABLY BELOW NORMAL WED
WITH TEMPS RETURNING TO NORMAL THU.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1216 AM CDT FRI AUG 22 2014

AT FIRST GLANCE...CONVECTION DURING THE REMAINDER OF THE NIGHT
SHOULD REMAIN TO THE EAST OF THE TERMINALS BUT A HIT OR MISS STORM
MAY STILL DEVELOP PRIMARILY TOWARDS KGRI IN THE VCNTY OF A LLVL
BOUNDARY. WITH FAIRLY LIGHT WINDS AND IN PRESENCE OF LLVL MOISTURE
FOG DEVELOPMENT IS POSSIBLE TOWARD MORNING WITH THE HRRR THE MOST
ROBUST WITH DEVELOP ALONG THE PLATTE RIVER AND MORE SO FOR KGRI VS
KEAR. WILL CONTINUE TO MONITOR TRENDS FOR THIS. A WARM FRONTAL
BOUNDARY IS PROGGED TO STALL SOUTH OF THE TERMINALS THIS AFTERNOON
THEN LIFT NORTHWARD THIS EVENING AND TONIGHT. THE FRONT WILL AGAIN
BE THE FOCUS FOR SHOWERS AND STORMS AND SEVERE WEATHER IS
POSSIBLE. BEST TIMING FOR CONVECTION IS DURING THE LATTER TAF
HOURS.


&&

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

$$

SHORT TERM...FAY
LONG TERM...HALBLAUB
AVIATION...FAY



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