Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 221156
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
656 AM CDT SUN MAY 22 2016

.UPDATE...
Issued at 643 AM CDT Sun May 22 2016

A few showers have popped up just to the southwest of the CWA.
HRRR looks like it is handling them fairly well and has them
moving over our southwestern counties and then dissipating before
noon. Added some low pops in our southern counties for a few hours
this morning. Otherwise think that most of the precip will hold
off until late this afternoon or evening.

&&

.SHORT TERM...(Today through Monday)
Issued at 401 AM CDT Sun May 22 2016

Thunderstorm chances and how severe they get will be the primary
forecast issue for the period.

The upper ridge just east of the Red River currently will move
eastward today, allowing southwesterly flow aloft to pick up and
the pattern to become more active. The surface trough over eastern
Montana will strengthen and move east, bringing even stronger
winds. 850mb winds get up to the 35 to 40 kt range this afternoon
and the boundary layer will be well mixed. Could get close to
advisory criteria but for now will keep any headlines out. A
greater threat will be fire weather for the far eastern tier as
discussed below.

Most of our counties will see increasing low level moisture
throughout the day. Destabilization could be impacted by clouds,
but some CAPE values up to 1500 J/kg are possible. Convergence
along the surface trough axis is not particularly strong, so will
have to look at weak shortwaves coming through the southwesterly
flow for forcing. The most prominent is still rotating through
southern California at the base of the main trough and should
bring some decent chances tonight. Less certain is earlier this
afternoon and in the evening when the instability is the best. A
few of the CAMs bring in some activity in the early afternoon,
while the HRRR and RAP are less impressive. Will continue to keep
POPs fairly low before 00Z but will start ramping them up in the
evening. Included a mention of severe in the evening as the
probabilities seem decently high. Will have to watch rainfall
amounts later tonight as the main shortwave comes out and some of
the short range models and even the NAM go to town with high QPF
in our southern counties.

Southwesterly flow aloft continues into Monday with the main
shortwave still moving across the eastern CWA during the morning
hours. Continued to keep POPS fairly high during the morning, then
have some more scattered activity into the afternoon in the
eastern tier as there could be some redevelopment over the surface
trough axis sitting over the area. NAM has some CAPE near 2000
J/kg over our southeast by afternoon but seems overdone on low
level moisture at this point. Temps will be limited by rainfall in
the east, but should again approach the 80 mark in the Red River
Valley on Monday.

.LONG TERM...(Monday night through Saturday)
Issued at 401 AM CDT Sun May 22 2016

Monday night through Tuesday night...Southwesterly flow aloft
continues. The surface pattern is fairly nebulous and convective
activity will depend on weak shortwaves aloft moving through.
Timing of these sort of features is difficult to nail down, but at
this point it seems we will have a bit of a break from precip
Monday night behind the stronger shortwave, then chances again for
Tuesday and Tuesday night as more weak waves move through.
Temperatures will continue to be fairly warm with highs in the
upper 70s to mid 80s and lows in the 50s.

Wednesday through Saturday...Split flow remains across North America
with southern stream over the states and the northern stream over
Canada. Southern stream de- amplifies while northern stream
amplifies a bit.

The ECMWF is faster than the GFS for the most part. The ECMWF was
also trending farther west over the last couple models runs. Will
blend the GFs and ECMWF.

High temperatures were decreased a degree or two for Wed. High temps
wee increased two to four degrees for Thu, increased about two
degrees for Fri, and increased one to three degrees for Sat.

&&

.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 643 AM CDT Sun May 22 2016

Ignoring the false report of low ceilings at KDVL, all sites are
VFR as high clouds have been moving in from the west. CIGs should
drop slowly throughout the day as lower clouds and better moisture
come in from the west. KDVL could see some MVFR conditions around
mid day. LLWS will go away in the next few hours and southerly
winds will pick up as we begin to mix out. Gusts up above 25 kts
will arrive this afternoon. Winds will begin to go down by sunset,
and storms will move in from the west this evening. For now have
VCTS mention...starting in the KDVL area around shortly before
sunset and moving into the central TAF sites around midnight. Have
the convection chances continuing through the end of the period so
kept the VCTS mention through 12Z.

&&

.FIRE WEATHER...
Issued at 401 AM CDT Sun May 22 2016

Changed fire weather watch to red flag warning for eastern three
counties of Lake of the Woods, Beltrami, and Hubbard. Relative
humidities will decrease to around 25 percent this afternoon. Winds
will be south at 15 to 20 mph with higher gusts. Not quite critical
fire weather category. However with dry fuels will go with a Red
Flag warning for this afternoon.

&&

.FGF Watches/Warnings/Advisories...
ND...None.
MN...Red Flag Warning from noon today to 7 PM CDT this evening for
     MNZ006-009-017-024.

&&

$$

UPDATE...JR
SHORT TERM...JR
LONG TERM...JR/Hoppes
AVIATION...JR
FIRE WEATHER...Hoppes



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