000
FXUS63 KLBF 251140
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
640 AM CDT SAT MAY 25 2013

.SYNOPSIS...
ISSUED AT 421 AM CDT SAT MAY 25 2013

AT 08Z...THE OUTFLOW BOUNDARY FROM CONVECTION LAST NIGHT IS QUITE
PROMINENT WITH THE NARROW LINE OF INTENSE CONVECTION STILL SHOWING
IN RADAR REFLECTIVITY. RADAR DERIVED WIND PROFILES SHOW THE LOW
LEVEL JUT CONTINUING INTO AT LEAST NORTHWEST KANSAS. THE NEBRASKA
PROFILERS ARE INDICATING THE EFFECTS OF THE OUTFLOW BOUNDARY AND ARE
NOT REPRESENTATIVE OF THE PROFILES ON THE WIDER SCALE. ANALYSIS OF
THE MSL DATA SHOWED LOW PRESSURE CENTERED OVER NORTHEAST COLORADO
WITH A WARM FRONT ACROSS NORTHERN KANSAS NEAR THE NEBRASKA STATE
LINE. DEWPOINTS OF 60F EXTENDED TO NEAR THE NEBRASKA LINE WITH 50 OR
HIGHER INTO NORTHERN SOUTH DAKOTA. WATER VAPOR IMAGERY INDICATED A
SMALL VORTICITY MAX OVER THE SURFACE LOW AND ANOTHER DEVELOPING WAVE
WITH THE INFLECTION POINT NEAR THE NEBRASKA-WYOMING-COLORADO TRIPLE
POINT.

&&

.SHORT TERM...(TODAY)
ISSUED AT 421 AM CDT SAT MAY 25 2013

THERE IS A LOT OF UNCERTAINTY REGARDING THE TIME AND LOCATION OF
CONVECTIVE INITIATION THIS AFTERNOON. THE BOUNDARY LEFT FROM THE
CONVECTION LAST NIGHT IS A LOGICAL START FOR TRYING TO EVALUATE THE
LOCATION. HOWEVER...THE LOW LEVEL JET COULD RECOVER BY LATE
AFTERNOON AND START FEEDING MOISTURE INTO WESTERN AND SOUTHWEST
NEBRASKA ONCE AGAIN. THE SHORT RANGE MODELS DO NOT APPEAR TO HAVE
THE LOCATION OF THE CONVECTIVE OUTFLOW BOUNDARY IN THEIR
PROJECTIONS...SO THE RETURN FLOW INDICATED BY THE SHORT RANGE MODELS
MAY NOT BE RELIABLE. STILL...THEY DO BRING A SURFACE BOUNDARY ACROSS
SOUTHERN NEBRASKA. AS A RESULT...WE SHOW A RAPID INCREASE IN
PRECIPITATION PROBABILITY  FROM LATE THIS AFTERNOON TO EARLY
EVENING.

.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 421 AM CDT SAT MAY 25 2013

THE FORECAST FOR THE NEXT WEEK IS FULL OF THUNDERSTORM CHANCES AS
THE GENERAL UPPER LEVEL PATTERN STAYS FAIRLY STAGNANT WITH A
LONGWAVE TROUGH TO THE WEST AND A STRONG RIDGE OVER THE EAST
COAST.

STARTING TONIGHT...THERE IS UNCERTAINTY TO THE COVERAGE OF
THUNDERSTORMS AND THE LOCATION BEYOND 26.00Z DUE TO UNCERTAINTY TO
WHERE STORMS WILL DEVELOP THIS AFTERNOON. THINKING THE SURFACE LOW
WILL BE OVER EAST CENTRAL COLORADO AT 26.00Z WITH A WARM FRONT
EXTENDING TO THE NORTHEAST ACROSS THE FORECAST AREA. THE LOW LEVEL
JET DOES INCREASE IN THE EVENING...BUT AGAIN...THERE ARE
DIFFERENCES IN ITS STRENGTH AND WHERE ITS MAIN FOCUS WILL BE. NAM
VEERS THE JET OFF TO THE EAST EARLY IN THE EVENING...WHILE THE GFS
FOCUSES OVER THE WARM FRONT ACROSS THE LOCAL AREA. THIS MAKES A
LARGE DIFFERENCE...FROM LOTS OF CONVECTION THROUGH THE EVENING TO
JUST A LITTLE. ASSUMING THE LOCATION OF THE WARM FRONT ACROSS THE
CENTRAL PART OF THE FORECAST AREA...THE HIGHER CHANCES FOR
CONVECTION LOOK TO BE OVER NORTH CENTRAL NEBRASKA. BUT AT THIS
POINT...WITH THE AMOUNT OF UNCERTAINTY DID NOT MAKE MUCH
ADJUSTMENTS TO THE PRECIPITATION FORECAST. ONCE THINGS START TO
EVOLVE THROUGH THE DAY THIS WILL BECOME MORE CLEAR AND CAN BE
CLEANED UP WITH LATER FORECAST UPDATES.

FOR SUNDAY...MORE OF THE SAME AS THE SURFACE LOW STAYS FAIRLY
STATIONARY OVER EASTERN COLORADO. MODELS ARE PUSHING THE WARM
FRONT NORTH INTO SOUTH DAKOTA...AND THE SOUTHERLY FLOW SHOULD
CONTINUE TO BRING IN PLENTY OF MOISTURE AHEAD OF THE SYSTEM WITH
DEWPOINTS IN THE 50S AND 60S FOR ALMOST THE ENTIRE FORECAST AREA.
FORECAST SOUNDINGS ARE SHOWING A DECENT CAP IN PLACE IN THE WARM
SECTOR. BUT...STILL THINK WILL GET CONVECTION TO FIRE OVER THE
HIGHER ELEVATED PARTS OF THE AREA AT LEAST AS THE CAP LOOKS TO
BREAK OVER THE HIGH PLAINS. ALSO...THERE IS INDICATIONS OF A WEAK
SHORTWAVE MOVING ACROSS THE AREA IN THE AFTERNOON WHICH COULD HELP
CONVECTION DEVELOP IN THE AFTERNOON. AGAIN...THE LOW LEVEL JET
CRANKS UP IN THE EVENING...SO IF STORMS DO DEVELOP...WILL HAVE
SOMETHING FEEDING THEM AS THEY MOVE EAST ACROSS THE FORECAST AREA.

FOR MONDAY...MORE CONVECTION EXPECTED FOR MONDAY AS ANOTHER
SHORTWAVE TROUGH PUSHES ACROSS THE AREA. CURRENT TIMING LOOKS BEST
FOR THE AFTERNOON HOURS...WHICH WOULD AGAIN PROMOTE THUNDERSTORM
CHANCES ACROSS MUCH OF THE FORECAST AREA.

BOTH DAYS...ANY STORMS WOULD HAVE THE POTENTIAL TO BE
SEVERE...WITH GOOD DEEP LAYER SHEAR TO PROMOTE ORGANIZED STORMS.
LARGE HAIL AND DAMAGING WINDS WOULD BE THE PRIMARY THREAT FROM ANY
STORMS...BUT CAN/T RULE OUT THREATS FOR TORNADOES...ESPECIALLY
DURING THE EARLY PARTS OF THE STORMS AND NEAR THE WARM FRONT.

TUESDAY THROUGH THURSDAY...THE LONGWAVE TROUGH WILL EVENTUALLY
BEGIN TO LIFT NORTHEAST. AGAIN...THUNDERSTORM CHANCES WILL STAY IN
THE FORECAST EVERY DAY AS THIS OCCURS. THEN BY THE END OF THE DAY
FRIDAY...THERE IS INDICATIONS THAT THE UPPER LOW WILL LIFT NORTH
INTO THE CENTRAL PLAINS. THIS COULD MEAN A COOL WEEKEND FOR THE
FORECAST AREA...AND TEMPERATURES FOR THE LATTER PART OF THE WEEK
ARE QUITE A BIT COOLER THAN THE FIRST HALF OF THE WEEK.

SOMETHING ELSE OF CONCERN WILL BE NEARLY DAILY OPPORTUNITIES
/THROUGH WEDNESDAY/ FOR STRATUS TO DEVELOP ACROSS PORTIONS OF THE
AREA AS MOISTURE CONTINUES TO BE PULLED INTO THE AREA AHEAD OF
THE SURFACE LOW. DO EXPECT STRATUS TO BURN OFF BY LATE MORNING
EACH DAY TO ALLOW FOR SUFFICIENT WARMING TO REACH FORECAST HIGHS.
THESE HIGHS WILL BE ABOVE NORMAL FOR MUCH OF THE FORECAST AREA
THROUGH MONDAY AND TUESDAY WITH HIGHS IN THE 80S...AND EVEN LOW
90S IN PLACES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 639 AM CDT SAT MAY 25 2013

THUNDERSTORMS ARE THE MAIN CONCERN WITH THE FORECAST THIS MORNING.
DUE TO THE ENVIRONMENT CREATED BY THE THUNDERSTORMS THAT OCCURRED
LAST NIGHT...THERE IS SIGNIFICANT UNCERTAINTY WITH THE LOCATION AND
TIMING OF THUNDERSTORM DEVELOPMENT. CURRENT INDICATIONS ARE THAT
THEY WILL DEVELOP AFTER 21Z IN NORTHEAST COLORADO AND OVER THE
NORTHERN NEBRASKA PANHANDLE. THE STORMS THAT DEVELOP IN NORTHEAST
COLORADO WILL PROBABLY PASS JUST SOUTH AND EAST OF LBF WHILE THOSE
THAT DEVELOP IN THE NEBRASKA PANHANDLE ARE EXPECTED AFFECT VTN LATE
THIS EVENING. AFTER THAT...THEY WILL MOST LIKELY MOVE EAST TO THE
ANW AND ONL AREAS. IN THEIR WAKE...LEFTOVER MOISTURE AND
EAST-SOUTHEAST WIND IS EXPECTED TO RESULT IN THE DEVELOPMENT OF
STRATUS CEILINGS IN NORTHERN NEBRASKA WITH CEILING BELOW 1000 FEET
AGL IN VTN...MHN...TIF AND ANW AFTER 08Z.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...SPRINGER
SHORT TERM...SPRINGER
LONG TERM...BROOKS
AVIATION...SPRINGER