Area Forecast Discussion
Issued by NWS Hastings, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KGID 190845
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
345 AM CDT SAT APR 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT APR 19 2014

MAP ANALYSIS INDICATES AN UPPER TROPOSPHERIC RIDGE AXIS EXTENDING
FROM THE UPPER MISSISSIPPI VALLEY TO THE SOUTHERN PLAINS. AN UPPER
TROPOSPHERIC CLOSED LOW IS NOTED OVER THE SOUTHEASTERN
CONUS...ANOTHER OVER NORTHERN MONTANA...AND ONE MORE OVER THE
SOUTHWESTERN CONUS. ENHANCED UPPER TROPOSPHERIC JET ENERGY EXTENDS
ALONG TWO BRANCHES ACROSS/NEAR THE CONUS...WITH ONE BRANCH OVER
SOUTHERN PORTIONS OF THE CONUS...AND THE OTHER EXTENDING FROM THE
NORTHWESTERN CONUS EASTWARD INTO THE NORTHERN PLAINS AND
NORTHEASTERN CONUS. OUR AREA REMAINS IN BETWEEN THE TWO BRANCHES
AND AS A RESULT...UPPER TROPOSPHERIC FLOW OVER OUR AREA REMAINS
FAIRLY WEAK...ONLY MAXING OUT AT AROUND 60KTS NEAR 35000FT AGL PER
00Z SOUNDING DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY
INDICATES INCREASED UPPER TROPOSPHERIC MOISTURE EXTENDING FROM THE
SOUTHERN PLAINS...NORTH INTO THE CENTRAL HIGH PLAINS AND PORTIONS
OF THE NORTHERN PLAINS. MUCH OF THIS INCREASED UPPER TROPOSPHERIC
MOISTURE REMAINS WEST OF OUR AREA...BUT IS ATTEMPTING TO MOVE
EAST. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE EXISTS
ACROSS NORTHEASTERN COLORADO...AS WELL AS ACROSS THE DAKOTAS. A
LOWER TROPOSPHERIC BAROCLINIC ZONE IS ALSO NOTED EXTENDING FROM
NORTH CENTRAL SOUTH DAKOTA INTO WESTERN NEBRASKA AND NORTHEASTERN
COLORADO. THE LOWER TROPOSPHERIC WIND FIELD ACROSS OUR AREA
REMAINS FROM THE SOUTH/SOUTHEAST AS A RESULT.

GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST THE UPPER TROPOSPHERIC LOW OVER NORTHERN MONTANA WILL MOVE
EAST/NORTHEAST INTO PORTIONS OF THE NORTHERN PLAINS AND SOUTH
CENTRAL CANADA THROUGH THE NEXT 24 HOURS. THE UPPER TROPOSPHERIC
LOW OVER THE SOUTHWESTERN CONUS IS EXPECTED TO WEAKEN AS IT SLOWLY
MOVES EAST INTO NEW MEXICO. AT THE SURFACE...THE AREA OF LOW
BAROMETRIC PRESSURE OVER THE DAKOTAS IS EXPECTED TO MOVE
EAST/NORTHEAST...ALONG WITH THE UPPER TROPOSPHERIC LOW...DURING
THE NEXT 24 HOURS. THE AREA OF LOW BAROMETRIC PRESSURE OVER
NORTHEASTERN COLORADO IS EXPECTED TO WEAKEN AS IT SLOWLY MOVES
INTO WESTERN KANSAS. THE ASSOCIATED LOWER TROPOSPHERIC BAROCLINIC
ZONE IS EXPECTED TO SLOWLY MOVE EAST/SOUTHEAST THROUGH THE NEXT 24
HOURS...LIKELY MOVING INTO FAR NORTHWESTERN PORTIONS OF OUR CWA BY
MID TO LATE THIS MORNING...AND MOVING INTO SOUTHEASTERN PORTIONS
OF OUR CWA BY 12Z SUNDAY.

AN OVERALL LACK IN OMEGA SHOULD PRESENT DRY CONDITIONS TO OUR
AREA THROUGH MID-AFTERNOON. BY LATE THIS AFTERNOON HOWEVER...LOWER
TROPOSPHERIC CONVERGENCE ALONG THE BAROCLINIC ZONE APPEARS AS
THOUGH IT WILL BE SUFFICIENT FOR CONVECTIVE INITIATION...A
SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL
GFS...EC AND SREF-MEAN...AS WELL AS SIMULATED REFLECTIVITY FROM
THE 4KM WRF-NMM. GIVEN THE OVERALL LACK IN SYNOPTIC-SCALE
OMEGA...IT APPEARS ANY SUCH CONVECTIVE ACTIVITY WILL BE DEPENDENT
UPON FORCING ALONG/NEAR THE BAROCLINIC ZONE...WHICH MEANS
CONVECTIVE ACTIVITY WILL LIKELY BE ISOLATED TO PERHAPS SCATTERED
AT BEST THIS AFTERNOON INTO THIS EVENING. GIVEN ALL THIS...WENT
AHEAD WITH 20-30% POPS ACROSS MUCH OF THE CWA STARTING 21Z...WITH
THE HIGHEST POPS RELEGATED TO AN AREA ROUGHLY WITHIN 25 MILES OF A
LINE FROM OSCEOLA...TO HASTINGS AND PHILLIPSBURG WHICH IS WHERE
THE BAROCLINIC ZONE IS EXPECTED TO BE POSITIONED LATE THIS
AFTERNOON INTO THIS EVENING.

HEADING INTO THE OVERNIGHT HOURS TONIGHT...THE NAM...OPERATIONAL
GFS...EC AND SREF-MEAN ALL SUGGEST A ~40KT LOW LEVEL JET AXIS WILL
DEVELOP FROM SOUTHWESTERN KANSAS INTO SOUTHEASTERN NEBRASKA. LOWER
TROPOSPHERIC THERMAL ADVECTION ALONG THIS JET AXIS WILL LIKELY
HELP INCREASE SPATIAL COVERAGE OF THE CONVECTIVE
ACTIVITY...ESPECIALLY ACROSS THE SOUTHEASTERN TWO-THIRDS OF OUR
CWA...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS...EC AND SREF-MEAN. GIVEN THIS...WENT AHEAD
WITH 30-70% POPS ACROSS MUCH OF THE CWA 03- 06Z. IT THEN APPEARS
CHANCES FOR PRECIPITATION WILL DIMINISH ACROSS OUR CWA AFTER 06Z
AS THE LOW LEVEL JET AXIS SHIFTS OFF TO THE EAST...MORE INTO THE
MISSOURI RIVER VALLEY. AS A RESULT...WENT AHEAD AND TAPERED POPS
ACROSS MUCH OF OUR AREA 06Z ONWARD.

GUIDANCE FROM THE NAM AND OPERATIONAL GFS SUGGEST 0-1KM MLCAPE
VALUES OF AROUND 1000J/KG WILL BE IN EXISTENCE ACROSS PORTIONS OF
OUR AREA ALONG AND HEAD OF THE ADVANCING BAROCLINIC ZONE LATE THIS
AFTERNOON AND EVENING. THESE SAME SETS OF GUIDANCE ALSO SUGGEST
DEEP- LAYER BULK SHEAR VALUES OF 20-30KTS WILL BE IN EXISTENCE
ACROSS THE AREA. GIVEN ALL THIS...IT APPEARS POSSIBLE A FEW OF THE
UPDRAFTS LATE THIS AFTERNOON INTO THIS EVENING COULD BE STRONG
ENOUGH TO PROMOTE A THREAT OF LARGE HAIL...WITH RESULTANT
DOWNDRAFTS PERHAPS PROMOTING AN OCCASIONAL STRONG TO SEVERE WIND
GUST. GIVEN THE ANTICIPATED POSITION OF THE LOW LEVEL BAROCLINIC
ZONE BY LATE THIS AFTERNOON...WILL GO AHEAD AND OUTLOOK LOCATIONS
ALONG AND SOUTHEAST FOR A LINE FROM ALMA...TO GRAND ISLAND AND
OSCEOLA FOR STRONG TO SEVERE THUNDERSTORM ACTIVITY BETWEEN 21Z AND
03Z. LOSS OF DIABATIC HEATING POST-SUNSET SHOULD PROMOTE A
SIGNIFICANT DROP IN POTENTIAL INSTABILITY AND EVEN WITH THE
PRESENCE OF THE LOW LEVEL JET...IT SEEMS UNLIKELY STRONG TO SEVERE
CONVECTION WILL BE OBSERVED BEYOND 03Z TONIGHT.

AN INCREASING LOWER TROPOSPHERIC PRESSURE GRADIENT AHEAD OF THE
APPROACHING BAROCLINIC ZONE WILL LIKELY PROMOTE A STIFF SURFACE
WIND ACROSS PORTIONS OF THE CWA TODAY. THAT BEING SAID...THE
SURFACE WIND WILL LIKELY DIMINISH QUITE A BIT ACROSS ALL AREAS BY
MID-AFTERNOON AS THE BAROCLINIC ZONE MOVES INTO THE AREA.
STILL...MET/NAM AND MAV/GFS GUIDANCE SUGGEST A SUSTAINED WIND OF
AROUND 24KTS...ALONG WITH GUSTS NEAR 32KTS...WILL BE POSSIBLE
ACROSS PORTIONS OF OSBORNE AND MITCHELL COUNTIES BETWEEN LATE THIS
MORNING AND EARLY THIS AFTERNOON. GIVEN ALL THIS...WILL GO AHEAD
AND OUTLOOK STRONG WIND IN THE HWO FOR EXTREME SOUTHEASTERN
PORTIONS OF THE CWA.

CONTINUED SOUTHERLY LOWER TROPOSPHERIC FLOW AND RESULTANT WARM
AIR ADVECTION WILL PROVIDE VERY WARM DAY FOR THOSE LOCATIONS AHEAD
OF THE BAROCLINIC ZONE TODAY...WHICH WILL BASICALLY BE THE
SOUTHEASTERN TWO-THIRDS OF OUR CWA WHERE HIGHS IN THE UPPER 70S TO
LOWER 80S ARE CURRENTLY FORECAST. FARTHER NORTHWEST HOWEVER...BACK
BEHIND THE BAROCLINIC ZONE...A COOLER LOWER TROPOSPHERIC AIR MASS
WILL LIKELY PROMOTE TEMPERATURE READINGS IN THE LOWER 70S.
CONTINUED SOUTHERLY LOWER TROPOSPHERIC FLOW...ALONG WITH
INCREASING CLOUD COVER AND PRECIPITATION...WILL LIKELY KEEP
TEMPERATURE READINGS FROM FALLING OFF ALL THAT FAR ACROSS THE
SOUTHEASTERN ONE-HALF OF OUR CWA TONIGHT...WITH OVERNIGHT LOWS IN
THE UPPER 50S TO NEAR 60 CURRENTLY FORECAST. ONCE AGAIN
HOWEVER...LOCATIONS FARTHER NORTHWEST BACK BEHIND THE BAROCLINIC
ZONE IN A COOLER LOWER TROPOSPHERIC AIR MASS...CAN EXPECT
OVERNIGHT TEMPERATURE READINGS IN THE UPPER 40S TO MID 50S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT APR 19 2014

LONG TERM DISCUSSION WILL BE ISSUED WITHIN AN HOUR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 100 AM CDT SAT APR 19 2014

VFR CONDITIONS FORECAST THROUGH THE NEXT 24 HOURS...BUT
SIGNIFICANT LOW LEVEL WIND SHEAR WILL CONTINUE THROUGH SUNRISE AND
CONVECTIVE ACTIVITY IS EXPECTED TO FINISH THE TAF PERIOD.

LITTLE IN THE WAY OF CLOUD COVER WILL BE OBSERVED AT GRI TO START
THE TAF PERIOD...BUT INCREASING HIGH-LEVEL CLOUDS NEAR 15000FT AGL
WILL BE OBSERVED DURING THE DAY SATURDAY...WITH A SCATTERED BUT
SHALLOW CUMULUS FIELD NEAR 5000FT AGL ALSO EXPECTED BY LATE
MORNING OR MIDDAY. INCREASING HIGH-LEVEL CLOUD COVER NEAR 10000FT
AGL...LIKELY THE RESULT OF DEEP CONVECTION ACROSS THE AREA...WILL
THEN BE NOTED TO FINISH THE TAF PERIOD. THE SURFACE WIND WILL
START THE TAF PERIOD FROM THE SOUTH/SOUTHEAST AT 12-17KTS. THE
APPROACH OF A LOWER TROPOSPHERIC BAROCLINIC ZONE WILL ALLOW THE
SURFACE WIND TO BECOME LIGHT AND VARIABLE BY 21Z...WITH THE WIND
THEN BECOMING NORTHEASTERLY POST-FROPA BY 02Z. A ~50KT JET STREAK
JUST ABOVE THE BOUNDARY LAYER WILL CONTINUE TO PROMOTE SIGNIFICANT
LOW LEVEL WIND SHEAR AT GRI THROUGH 15Z...AND SUCH HAS BEEN
PRESENTED IN THE TAF. DRY CONDITIONS ARE EXPECTED AT GRI THROUGH
MID TO LATE AFTERNOON. THE APPROACH/PASSAGE OF THE AFOREMENTIONED
BAROCLINIC ZONE HOWEVER WILL LIKELY PROMOTE ISOLATED TO PERHAPS
SCATTERED DEEP CONVECTION ACROSS THE AREA BY LATE AFTERNOON...WITH
A ~30% PROBABILITY OF SUCH ACTIVITY IMPACTING GRI. WENT AHEAD WITH
A PROB30 FOR CONVECTIVE ACTIVITY 22-02Z AS A RESULT. 02Z AND
BEYOND...GUIDANCE SUGGESTS CONVECTIVE ACTIVITY WILL INCREASE IN
SPATIAL COVERAGE ACROSS THE AREA AND AS A RESULT...WENT AHEAD WITH
PREVAILING CONVECTIVE ACTIVITY AT GRI 02Z ONWARD IN THE TAF.
VISIBILITY RESTRICTION IS NOT EXPECTED FOR THE MOST AT GRI DURING
THE TAF PERIOD...BUT SOME RESTRICTION TO ~6SM WILL BE POSSIBLE IN
RAINFALL IF/WHEN CONVECTION IS REALIZED AT GRI.

&&

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

$$

SHORT TERM...BRYANT
AVIATION...BRYANT



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.