000
FXUS63 KGLD 172003
AFDGLD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
203 PM MDT FRI MAY 17 2013

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 151 PM MDT FRI MAY 17 2013

ISOLATED THUNDERSTORMS IN NORTHEAST COLORADO WILL MOVE NORTHEAST
THIS EVENING AND MAY CLIP YUMA COUNTY. MODERATE INSTABILITY AND
WEAK SHEAR SUGGEST ANY STORM THIS EVENING MAY BE ABLE TO PRODUCE
MARGINALLY SEVERE HAIL AND GUSTY WINDS. THIS ACTIVITY WILL END BY
MIDNIGHT. OVERNIGHT...STRATUS AND FOG IS EXPECTED TO OVERSPREAD
THE AREA FROM THE SOUTH AND PERSIST INTO SATURDAY MORNING. DENSE
FOG WILL BE POSSIBLE. ASSUMING WE GET A FEW HOURS OF CLEARING
SATURDAY MORNING AND EARLY AFTERNOON...MODELS FORECAST A VERY
UNSTABLE ENVIRONMENT IN NORTHWEST KANSAS AND SOUTHWEST NEBRASKA BY
MID AFTERNOON. A SHORTWAVE TROUGH WILL BE EJECTING ACROSS THE
ROCKIES WITH RESULTING STEEP LAPSE RATES. AT THE
SURFACE...CYCLOGENESIS WILL OCCUR IN SOUTH CENTRAL COLORADO WITH
SURFACE LOW MOVING QUICKLY NNE. COLD FRONT/DRY LINE WILL LIKELY BE
INITIATING MECHANISM...WITH BIGGEST QUESTION BEING WHERE IT
EXACTLY SETS UP IN THE AFTERNOON. ONCE UPDRAFTS DEVELOP...STORMS
SHOULD QUICKLY BECOME SEVERE WITH VERY LARGE HAIL BEING THE MAIN
THREAT. A TORNADO OR TWO WILL ALSO BE POSSIBLE WITH DEEP LAYER
SHEAR UP TO 40KTS SUPPORTIVE OF SUPERCELLS.

.LONG TERM...(MONDAY THROUGH THURSDAY) ISSUED AT 244 AM MDT
FRI MAY 17 2013

GFS AND ECMWF MODELS PLACING THE CLOSED UPPER LEVEL LOW AROUND SOUTH
DAKOTA AND NEBRASKA FOR MONDAY MORNING...WITH STRONGEST 500 MB JET
OF 60 KNOTS TO THE CENTRAL AND EASTERN PART OF KANSAS. THE UPPER
LEVEL LOW IS PREDICTED TO STAGNATE OVER THE UPPER PLAINS FOR TUESDAY
AND INTO WEDNESDAY MORNING UNTIL AN UPPER LEVEL SHORTWAVE RIDGE
MOVES INTO THE TRI STATE AREA.  THE SHORTWAVE RIDGE WILL BUILD INTO
A HIGH AMPLITUDE PATTERN FOR THURSDAY AND FRIDAY...WITH AN ELONGATED
TROUGH TO THE WEST. THE TROUGH COULD MOVE INTO THE REGION FOR NEXT
WEEKEND...BRINGING ACTIVE WEATHER TO THE REGION.  STRONGEST LOW
LEVEL JET OF 35-40 KNOTS LOOKS TO MOVE INTO WESTERN KANSAS OVERNIGHT
MONDAY AND TUESDAY MORNING.  THETA E VALUES AT 850 MB ARE GENERALLY
BETWEEN 300 AND 310 K...PROVIDING MARGINAL MOISTURE FOR DEEP
CONVECTION DEVELOPMENT.  GFS IS PLACING HIGHER THETA E VALUES INTO
KANSAS FOR LATER NEXT WEEK...WITH VALUES AROUND 340 K.  THIS COULD
PROVIDE ENOUGH MOISTURE FOR AIR MASS THUNDERSTORMS TO DEVELOP WITH
PROPER DAYTIME HEATING.

SURFACE LOW PRESSURE WILL STAY IN THE NORTHERN PLAINS FOR MONDAY AND
TUESDAY...PROVIDING SOME UNSETTLED WEATHER TO THE REGION.  CAPE
VALUES WILL REMAIN LOW...WITH POSSIBILITIES OF REACHING 500 J/KG.
SOME COLD AIR ADVECTION WITH NORTHWESTERLY WINDS IS PRESENT IN THE
MODELS...FILTERING INTO THE REGION MONDAY AND TUESDAY...WHICH WILL
KEEP TEMPERATURES MORE SEASONABLE IN THE MID TO UPPER 70S.  SURFACE
DEW POINTS WILL BE IN THE UPPER 30S AND LOWER 40S FOR MONDAY AND
TUESDAY WITH SURFACE THETA E VALUES BETWEEN 310 AND 320 K...WHICH
WILL PROVIDE MARGINAL MOISTURE FOR STORMS TO DEVELOP. LIFTED INDEX
VALUES FOR THE PERIOD GENERALLY ARE AROUND -2 CELSIUS.  GFS HAS
HIGHER VALUES FOR THURSDAY AND FRIDAY...WHERE LIFTED INDEX VALUES
WILL REACH BETWEEN -3 AND -6 CELSIUS.  GFS CAPE VALUES FOR FRIDAY
COULD REACH BETWEEN 1000 AND 2000 J/KG ACROSS THE CWA...PROVIDING
CHANCES FOR STRONGER THUNDERSTORMS TO DEVELOP.  HOWEVER...THE ECMWF
INDICATES SURFACE HIGH PRESSURE WITH LARGER CAPE VALUES FARTHER TO
THE WEST OF THE CWA.  BECAUSE OF THE DIFFERENCES IN THE MODEL
RUNS...CONFIDENCE IN STRONG THUNDERSTORM OCCURRENCE FOR FRIDAY
REMAINS LOW AT THIS POINT.

STAGNANT LOW PRESSURE SYSTEM WILL BRING CHANCES FOR RAIN SHOWERS AND
COOLER TEMPERATURES FOR MONDAY AND TUESDAY...WITH HIGH TEMPERATURES
REACHING THE LOW TO MID 70S.  HIGH PRESSURE WILL ENTER THE REGION
FOR WEDNESDAY AND THURSDAY...PROVIDING SUNNY SKIES AND TEMPERATURES
IN THE MID TO UPPER 70S.  A NEW STORM SYSTEM WILL DEVELOP TO THE
WEST FOR FRIDAY...BRINGING CHANCES FOR STRONG STORMS TO DEVELOP INTO
FRIDAY EVENING AND NEXT WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1128 AM MDT FRI MAY 17 2013

VFR CONDITIONS EXPECTED THROUGH THE AFTERNOON AND EVENING HOURS AT
BOTH KGLD AND KMCK. ISOLATED THUNDERSTORMS WILL DEVELOP OVER
NORTHEAST COLORADO THIS AFTERNOON AND MOVE INTO NEBRASKA...AND
WILL PROBABLY STAY NORTH OF BOTH TERMINALS. TONIGHT...APPEARS TO
BE A GOOD CHANCE OF FOG/STRATUS OVERSPREADING BOTH TERMINALS AFTER
MIDNIGHT WITH LOW CIGS AND RESTRICTED VISBYS PERISTING INTO
SATURDAY MORNING. LOWERED FLIGHT CATEGORIES TO IFR...VLIFR WILL BE
POSSIBLE.


&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

$$

SHORT TERM...024
LONG TERM...MCK
AVIATION...024