239
FXUS63 KGID 050120
AFDGID
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
820 PM CDT SAT JUL 4 2009
AVIATION
00Z KGRI TAF. BY FAR THE MAIN ISSUE DURING THIS TAF
PERIOD WILL BE CEILING AND VISIBILITY TRENDS...WITH SOMEWHAT LOW
CONFIDENCE ESPECIALLY LATE TONIGHT AND EARLY SUNDAY MORNING.
STARTING OFF...A PERSISTENT MVFR CLOUD REMAINS IN PLACE THIS
EVENING. THERE ARE ALSO SOME BRIEF...LIGHT RAIN SHOWERS IN THE
AREA BUT WILL LEAVE OUT MENTION OF PRECIPITATION DUE TO EXPECTED
LIMITED IMPACT. HAVE GENERALLY KEPT THE THEME OF THE PREVIOUS
FORECAST...WITH CEILINGS TRYING TO LIFT/SCATTER OUT INTO VFR RANGE
ABOVE 3000 FT BY LATE EVENING...BUT TIMING COULD BE OFF BY AN HOUR
OR TWO. WITH LINGERING LOW LEVEL MOISTURE...CLEARING SKIES AND
SURFACE HIGH PRESSURE BUILDING INTO THE REGION...FOG DEVELOPMENT
WILL AGAIN BE A POSSIBILITY TONIGHT. AGAIN...HAVE KEPT THEME OF
PREVIOUS FORECAST WITH MVFR VISIBILITIES A FEW HOURS EITHER SIDE
OF SUNRISE...BUT THERE IS SOME CONCERN THAT THINGS COULD TUMBLE
INTO IFR TERRITORY WITH CEILINGS AND/OR VISIBILITY. WILL KEEP A
MORE OPTIMISTIC APPROACH FOR NOW. ONCE ANY POTENTIAL FOG ISSUES
SUBSIDE SUNDAY MORNING...THE REST OF THE DAY SHOULD FEATURE
SCATTERED VFR CLOUDS AND LIGHT AND VARIABLE WINDS WITH THE CENTER
OF THE SURFACE HIGH NEARBY.
PREV DISCUSSION
/ISSUED 311 PM CDT SAT JUL 4 2009/
SHORT TERM...GOOD NORTH FLOW WITH YET ONE MORE SHORT WAVE WORKING
SOUTH ACROSS NEBRASKA AT THIS TIME...HELPING TO SPARK SPRINKLES OVER
NORTHERN NEBRASKA...INCREASE WINDS AND KEEP CLOUDS IN THE AREA. SEE
THOSE TRENDS CONTINUING TIL EARLY EVENING...BEFORE WINDS DROP OFF
SOME AND SPRINKLES DIE OUT. EXPECT CLOUDS TO LINGER THROUGH LATE
EVENING BEFORE WORKING OUT OF THE CWFA FROM NORTH TO SOUTH.
NUMERICAL GUIDANCE PICKING UP ON SOME LOWER VSBYS...AND THAT SEEMS
REASONABLE GIVEN LIGHT WINDS EXPECTED WITH SURFACE RIDGE MOVING
IN. MOISTURE DECREASES BUT IT ISN/T REAL DRY AIR...AND WE OFTEN
CATCH SOME FOG AS LOW CLOUDS CLEAR. ADDED PATCHY FOG TO THE
FORECAST FOCUSING IN ON THE RIVER VALLEYS OVER THE WESTERN/NORTHERN
CWFA WERE CLEARING WILL BE FIRST. THAT WILL HAVE TO BE WATCHED.
MILD DAY TOMORROW WITH LIGHT WINDS...AND JUST SCATTERED CLOUDS
AROUND IT WILL BE THE NICEST DAY OF THE WEEKEND FOR MOST AREAS.
AFTERNOON HIGHS WILL BE 5 TO 8 DEGREES BELOW NORMAL.
HAVE SCALED BACK THUNDERSTORM RISK FOR SUNDAY NIGHT. NOT MUCH
UPPER SUPPORT TO SPEAK OF BUT ISENTROPIC MAY SHIFT ENOUGH EAST TO
GET SOMETHING INTO THE WESTERN CWFA. HAVE PUSHED SMALL STORM RISK
TO ALONG/WEST OF HIGHWAY 183 AND FOR LATE SUNDAY NIGHT.
LONG TERM....LONG TERM...12Z MONDAY THROUGH SATURDAY. FORECAST
CONCERNS INCLUDE WARMING TEMPERATURES...ALONG WITH PRECIPITATION
CHANCES EARLY AND AGAIN LATE IN THE PERIOD.
STARTING OFF MONDAY MORNING...MAY HAVE SOME PRECIP LINGERING ACROSS
WESTERN PORTIONS OF THE CWA FROM SUNDAY NIGHT. VERY WEAK LLJ LINGERS
INTO THE MORNING HOURS...BUT ASSOCIATED WITH IT IS SOME ISENTROPIC
LIFT THAT COULD SUPPORT SOME WEAK ELEVATED CONVECTION. THE FOCUS FOR
ANY ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY MONDAY AFTERNOON AND
EVENING WILL STAY OVER THE WESTERN CWA. THE UPPER RIDGE AXIS IS
ORIENTED OVER THE ROCKIES ON MONDAY...WITH A LEE TROUGH IN PLACE AT
THE SURFACE. SOUTH/SOUTHEAST WINDS EAST OF THE LEE TROUGH ADVECT
MOISTURE NORTHWARD...CONTRIBUTING TO INCREASED INSTABILITY DURING
THE AFTERNOON. MAIN AREA FOR CONVECTIVE DEVELOPMENT WILL BE WELL
WEST OF THE CWA ACROSS THE HIGHER TERRAIN...BUT AS THESE STORMS MOVE
SOUTHEAST ABOARD THE NORTHWEST FLOW ALOFT...SOME COULD EVENTUALLY
WORK INTO THE WESTERN CWA DURING THE LATE AFTERNOON AND EVENING
HOURS. MODELS ALSO HINT AT A WEAK BOUNDARY SETTING UP NEAR THE
SOUTHWEST CWA...POSSIBLY PROVIDING ENHANCED LOCAL CONVERGENCE FOR A
FEW STORMS TO FIRE ALONG. GIVEN THESE FACTORS AND SOME SUBTLE WEAK
SHORTWAVE ENERGY STILL EMBEDDED WITHIN THE NORTHWEST FLOW
ALOFT...WILL CARRY SOME SMALL POPS ACROSS THE WEST MONDAY INTO
MONDAY EVENING. WILL KEEP THINGS DRY LATE MONDAY NIGHT THROUGH
TUESDAY NIGHT AS THE UPPER RIDGE SHIFTS EASTWARD OVER THE PLAINS.
STILL CANNOT TOTALLY RULE OUT SOME ISOLATED PRECIP SOMEWHERE ACROSS
THE AREA DURING THIS TIME WITH WEAK MID-LEVEL PERTURBATIONS STILL
AROUND ALONG WITH SOME NOCTURNAL LLJ PRESENCE...BUT NOTHING SOLID
ENOUGH AT THIS POINT TO CARRY PRECIP MENTION. TEMPERATURES WARM BOTH
MONDAY AND TUESDAY WITH THE AID OF SOUTHERLY WINDS AND RIDGE AXIS
SHIFTING IN...PUSHING HIGHS GENERALLY INTO THE 80S TO NEAR 90F ON
MONDAY AND INTO THE LOWER TO MID 90S TUESDAY.
THE UPPER RIDGE BUILDS OVER THE CENTRAL CONUS MID TO LATE
WEEK...BRINGING A RETURN OF HOT CONDITIONS FOR AT LEAST A FEW DAYS.
H85 TEMPS ARE PROGGED TO REACH THE LOWER TO MID 20S NORTHEAST TO
LOWER 30S SOUTHWEST...SUPPORTING HIGHS IN THE TRIPLE DIGITS ACROSS
THE SOUTH/SOUTHWEST. WILL GO AHEAD AND HIGHLIGHT THE ANTICIPATED HOT
SPELL IN THE HWO...ESPECIALLY FOR THE SOUTHERN CWA. A TROUGH RIDING
ACROSS SOUTHERN CANADA THEN SENDS A COOL FRONT SOUTH INTO THE
NORTHERN CWA ON THURSDAY. HOWEVER...VERY STRONG CAPPING WILL BE IN
PLACE WHICH WILL SUPPRESS ANY PRECIP DURING THE DAY ON THURSDAY. THE
FRONTAL BOUNDARY THEN STALLS OUT AND LINGERS OVER THE AREA INTO THE
WEEKEND. WILL CARRY SOME SMALL POPS THURSDAY NIGHT INTO SATURDAY DUE
TO THE FRONT HANGING AROUND. MID-LEVEL TEMPS STAY WARM UNDER THE
RIDGE...LIKELY CAPPING OFF CONVECTION DURING THE DAYTIME HOURS
EXCEPT FOR MAYBE ACROSS THE NORTH. LITTLE BETTER CHANCES WILL COME
DURING THE NIGHTTIME HOURS WITH SOME AID FROM THE NOCTURNAL LLJ.
GID WATCHES/WARNINGS/ADVISORIES
NE...NONE.
KS...NONE.
AVIATION...PFANNKUCH
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