534
FXUS63 KFGF 241926
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
226 PM CDT THU JUL 24 2008
SHORT TERM
FORECAST CHALLENGE CONTINUES TO BE CONVECTIVE CHANCES TONIGHT INTO
THE EARLY PART OF FRIDAY. MANY DIFFERENT AREAS TO WATCH FOR PCPN
DURING THIS TIME FRAME...BUT MODELS SEEM TO BE IN REASONABLE
AGREEMENT FOR OUR FA. WILL USE A MODEL BLEND FOR THIS FORECAST
PACKAGE.
TONIGHT...SFC TROUGH/DRY LINE STARTING TO SHOW UP NICELY ON
VISIBLE SATELLITE IMAGERY AND THE KMVX 88D...BASICALLY AT 19Z
ALONG A LINE FROM KROX TO KCKN TO EAST OF KJMS. A BAND OF ENHANCED
CUMULUS/TCU ARE EVIDENT ON VISIBLE SATELLITE IMAGERY ALONG THIS
LINE AND A FEW WEAK CELLS HAVE ALSO POPPED UP ON RADAR. LIKE
MENTIONED IN PRIOR DISCUSSIONS...NOT MUCH UPPER LEVEL SUPPORT TO
AID IN FURTHER DEVELOPMENT FOR THESE ECHOES. EVEN AT THE SFC...
EXTENSIVE LOW CLOUDS HAVE LIMITED THE AMOUNT OF HEATING TO THE
EAST OF THIS LINE OF CONVECTIVE DEVELOPMENT. THIS SFC BOUNDARY IS
PRETTY WEAK AND IS PROGGED TO SLOWLY MOVE EAST OF THE FA BY EARLY
EVENING. SPC MESOANALYSIS PAGE SHOWS THE BEST SFC BASED CAPE
AVAILABLE RIGHT ALONG/BEHIND THE FRONTAL BOUNDARY NOW. CLOUDS AND
LESS HEATING HAVE LIMITED THE AMOUNT OF SFC BASED CAPE OVER THE
EASTERN FA. 0-6KM SHEAR NOT OVERLY IMPRESSIVE EITHER...AT 20 TO
30KTS. THEREFORE THINK THE TSTMS INITIALLY WILL NOT BE TOO
STRONG...BUT IF THE CLOUDS AND HEATING DO GET GOING LATER THIS
AFTERNOON THERE COULD BE FLARE UPS. SPC DOES MAINTAIN A SLIGHT
RISK FOR SEVERE TSTMS EAST OF THIS SFC BOUNDARY TONIGHT.
OTHERWISE...IMPRESSIVE 500MB VORTICITY MAX WORKING ALONG THE
U.S./CANADIAN BORDER NOW HELPING FUEL SEVERAL AREAS OF TSTMS OVER
EASTERN MT AND WESTERN ND. DYNAMICS TO KEEP THESE STORMS GOING
WEAKEN THE FURTHER EAST THESE GET (AT LEAST INITIALLY)...BUT SOME
OF THESE COULD STRAY INTO THE WESTERN FA LATER. WITH THIS IN
MIND...WILL KEEP A BROADBRUSHED LOW CHANCE FOR TSTMS ACROSS THE
ENTIRE FA TONIGHT.
FRI...CURRENT MONTANA VORT WILL CROSS THE NORTHERN/EASTERN FA
DURING PEAK HEATING ON FRI. SINCE QUITE A FEW TSTMS WERE SPAWNED
NEAR THIS VORT TODAY...NOT OUT OF THE QUESTION THAT A FEW COULD
FIRE AGAIN FRI MORNING OR AFTERNOON. WILL LEAVE LOW PCPN CHANCES
JUST IN THE NORTHEAST FA FOR NOW AND SEE HOW LATER RUNS HANDLE
THIS.
SAT-SUN...SFC HIGH BUILDS INTO THE FA WITH FAIRLY LIGHT WINDS AND
QUITE A BIT OF SUN EXPECTED FOR THE WEEKEND. IN ADDITION...SFC DEW
POINTS DRY OUT QUITE A BIT TOO...WHICH WILL SET THE STAGE FOR MORE
COMFORTABLE CONDITIONS OUTDOORS.
LONG TERM [MON-THU]
MODELS IN GENERAL AGREEMENT SHOWING NE PAC/NW CONUS TROUGH...WC
CONUS RIDGE THROUGH THE PERIOD. MODELS ALSO IN AGREEMENT SHOWING
ENERGY TO TRAVEL FROM PAC NW THROUGH THE MEAN RIDGE. DETAILS
(TIMING/STRENGTH) CONCERNING THIS ENERGY STILL MUCH UNCERTAIN...
WILL MAKE NO CHANGE TO CURRENT FORECAST (LOW END POPS MON NIGHT-
WED). TEMPERATURES NEAR NORMAL...POSSIBLY SLIGHTLY ABOVE NORMAL BY
THE END OF THE WEEK IF THE MID-CONUS RIDGE STRENGTHENS AS MODELS
SUGGEST.
AVIATION
EXPECT MVFR CIGS TO BECOME SCT BY EVENING. MAIN CHALLENGE WILL
THEN BECOME THUNDER CHANCES. ALTHOUGH THUNDER POSSIBLE THIS
EVENING/OVERNIGHT THINK COVERAGE WILL BE TOO LIMITED FOR MENTION
IN TAF FORECAST.
FGF WATCHES/WARNINGS/ADVISORIES
ND...NONE.
MN...NONE.
GODON/TG
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