Area Forecast Discussion
Issued by NWS North Platte, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 KLBF 251721
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1221 PM CDT SAT JUL 25 2015

.SYNOPSIS...
ISSUED AT 324 AM CDT SAT JUL 25 2015

WEAK TEMPERATURE AND PRESSURE FIELDS MAKE IT A LITTLE DIFFICULT
PICKING OUT THE MAJOR PLAYERS IN THE WEATHER THIS MORNING. HAND
ANALYSIS OF THE 07Z MSL DATA REVEALS A FRONT ACROSS KANSAS INTO
NORTHEAST COLORADO AND EASTERN WYOMING. THERE IS ANOTHER BOUNDARY...
PROBABLY ASSOCIATED WITH OUTFLOW...ACROSS EAST CENTRAL TO SOUTHEAST
NEBRASKA. THE SATELLITE MICRO-WAVE DERIVED BLENDED PRECIPITABLE
WATER SHOWED AN INCH OR MORE SOUTH AND EAST OF A LINE FROM ONEILL
THROUGH MULLEN TO ALLIANCE. THE WATER VAPOR IMAGERY INDICATED A HINT
OF A BAROCLINIC LEAF IN NORTHWEST COLORADO.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT SAT JUL 25 2015

THE 0-2KM THETA-E/WIND PROJECTION SHOWS CONVERGENCE ALONG A
BOUNDARY...PROBABLY THE DRYLINE...DEVELOPING LATE THIS MORNING TO
EARLY AFTERNOON. HOWEVER...A FORECAST SOUNDING IN THE THETA-E
GRADIENT INDICATES A CAP NEAR 700MB UNTIL AFTER 22Z BUT A STRONG CAP
CONTINUES EAST OF THE THETA-E BOUNDARY THROUGH 00Z. THEREFORE...THE
CHANCES FOR CONVECTION WILL BE LOW WITH LESS THAN 25 PERCENT
PROBABILITY WEST OF A VALENTINE-NORTH PLATTE LINE AND 25-30 PERCENT
EAST OF THAT LINE.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 321 AM CDT SAT JUL 25 2015

SUNDAY AND MONDAY...ANOMALOUS UPPER TROUGH WILL BE DROPPING SEWD
INTO THE PAC NW AND THE MODELS ARE SIMILAR IN THEIR DEPICTION OF
THIS SCENARIO. AS THIS OCCURS THE RIDGE CENTERED ACROSS THE SOUTHERN
AND CENTRAL PLAINS AMPLIFIES AS HEIGHT FALLS ROUND THE BASE OF THE
TROUGH FURTHER WEST SUNDAY NIGHT. THE LOW LEVEL RESPONSE WILL BE TO
DEVELOP LOW PRESSURE ALONG THE LEE OF THE HIGHER TERRAIN...FAVORING
THE NRN HIGH PLAINS. THIS WILL CAUSE AN INCREASE IN SRLY WINDS
ACROSS WRN AND NC NEB DURING THE DAY SUNDAY AND ESPECIALLY SUNDAY
NIGHT AS THIS SYNOPTIC PATTERN IS ENHANCED BY THE HIGH PLAINS
NOCTURNAL LLJ. THE NAM AND THE GFS DIFFER ON THE DEPTH OF BL MIXING
THROUGH THE DAY SUNDAY WITH GFS BEING DEEPER AND THEREFORE MIXING
OUT LOW LEVL MOISTURE MORESO BY SUNDAY EVENING. THE NAM IS TEMPERED
WITH THE DEGREE OF MIXING AND THEREFORE HAS A MORE DISCERNABLE DRY
LINE SUNDAY AFTERNOON. IN THE END...BOTH MODELS BRING A SUBTLE PV
ANOMALY AROUND THE SRN PLAINS RIDGE AND FOCUS TSRA DEVELOPMENT ALONG
THE ERN PLAINS OF CO INITIALLY AND EXPANDING IN COVERAGE AS THE
STORMS ORIGINATING IN THE DRIER ATMOSPHERE REACH THE DEEPER
MOISTURE. CAMS ALSO HAVE THEIR DIFFERENCES...THE HIRES ARW DEVELOPS
A LARGE MCS WHILE THE NMM IS RELATIVELY QUIET. SO MANY DIFFS TO WORK
OUT BUT WILL SIDE WITH A SCENARIO THAT DEVELOPS WEAK CONVECTION IN
THE DRIER AIR FURTHER WEST AND MOVING EWD OVERNIGHT AND IS ENHANCED
BY THE LLJ. THE MARGINAL THREAT FOR DAMAGING WIND SEEMS
APPROPRIATE...BU HEAVY RAIN MAY ALSO BE AN ISSUE. A SIMILAR SETUP IS
IN PLACE FOR MONDAY AND MONDAY EVENING WITH THE MODELS AGAIN
DIFFERING ON HOW TO PROGRESS THE DRYLINE AS THE UPPER TROUGH MOVES
INTO THE NRN ROCKIES. THE RESULTING CONVECTIVE POTENTIAL DURING THE
AFTERNOON IS ALSO DIFFERENT...WITH THE NAM PROPAGATING THE MORNING
CONVECTION EWD ALONG THE LOW LEVEL THETA-E GRADIENT AND THIS SEEMS
REASONABLE. HOWEVER...VERY WARM MID LEVEL TEMPS MAY PROVE TO BE TOO
DESTRUCTIVE FOR CONVECTIVE UPDRAFTS IN THE WRN HALF OF THE AREA
DURING THE AFTERNOON MONDAY AND THEREFORE THE NEXT ROUND OF STORMS
WOULD COME MONDAY EVE/OVERNIGHT AND AGAIN BE SUSTAINED BY THE LLJ.
TEMPS SUNDAY AND MONDAY WELL INTO THE 90S AND MAY FLIRT WITH 100.

UPPER TROUGH AND ASSOCIATED MORE SUBSTANTIAL PV ANOMALY MOVES ACROSS
THE NRN PLAINS TUES INTO WED AND DRIVES A COLD FRONT SWD INTO THE
AREA BY TUESDAY NIGHT. THE CONTINUED MOIST SRLY FLOW AT LOW LEVELS
AND AROUND THE STRONG UPPER RIDGE CENTERED OVER THE SRN PLAINS WILL
ALLOW PW VALUES TO APPROACH 140-160 PERCENT OF NORMAL ACROSS THE
NERN PORTION OF THE AREA TUES NIGHT SO HEAVY RAIN WILL BE A
POSSIBILITY THOUGH DEPENDING ON TIMING OF THE FRONTAL PASSAGE. THE
FRONT SHOULD BE DRIVEN WELL SOUTH OF THE AREA WED AND THUR...WITH A
SIGNIFICANTLY COOLER AND DRIER AIRMASS IN PLACE FOR WED AND A
PORTION OF THURS.

AFTER THE UPPER TROUGH PASSES TO THE EAST THE UPPER RIDGE BEGINS TO
RE-ESTABLISH ACROSS THE SOUTHWEST U.S. WITH THE ACTIVE NRN STREAM
LOCATED ACROSS SRN CANADA INTO THE GREAT LAKES AND NE. THIS WILL
SIGNAL A RETURN TO AVERAGE OR SLIGHTLY ABOVE AVE TEMPS FOR THE END
OF THE WEEK AND INTO THE FIRST PART OF THE WEEKEND. SFC FOCUS FOR
ANY THUNDERSTORM DEVELOPMENT FRI AND SAT IS NEBULOUS AT BEST AND
ALTHOUGH SLIGHT CHCS ARE INCLUDED IN THE FCST CONFIDENCE IS LOW AS
THIS TYPE OF PATTERN WOULD NOT BE CONDUCIVE OF AN ACTIVE PATTERN FOR
THE HIGH PLAINS OF NEB.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1221 PM CDT SAT JUL 25 2015

FOR THE 18Z TAF ISSUANCE. FORECAST CONFIDENCE IN WHERE AND WHEN
CONVECTION DEVELOPS THIS AFTERNOON IS LOWER THAN AVERAGE. THAT
BEING SAID...A FEW SHOWERS ARE DEVELOPING TO THE WEST OF
KLBF...WITH A STRONGER THUNDERSTORM OVER KONL. ATTM THE BEST
FOCUS OF ADDITIONAL STORM DEVELOPMENT LOOKS TO LIE TO THE EAST OF
BOTH KLBF AND KVTN THIS AFTERNOON. EASTERN TERMINALS SUCH AS
KANW...KONL...AND/OR KBBW MAY SEE A STRONG OR SEVERE THUNDERSTORM
THIS AFTERNOON. OTHERWISE THE LATEST GUIDANCE INDICATES A 1/4SM
FOG AT KVTN AFTER 09Z SUNDAY MORNING...THIS WAS DISCOUNTED FOR
NOW...BUT WILL BE MONITORED IN FUTURE FORECASTS.

&&

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

$$

SYNOPSIS...SPRINGER
SHORT TERM...SPRINGER
LONG TERM...JWS
AVIATION...JACOBS


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