Area Forecast Discussion
Issued by NWS Grand Forks, ND

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377
FXUS63 KFGF 310448
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1148 PM CDT MON MAY 30 2016

.UPDATE...
Issued at 1148 PM CDT Mon May 30 2016

Made some tweaks to fit current radar trends. A few NDAWN sites in
the southern Red River Valley gusted above 40 mph, but as the
leading edge crossed the river there has been a downward trend.
Think that storms will continue to lift northeastward and weaken a
bit.

UPDATE Issued at 941 PM CDT Mon May 30 2016

Surface low continues to push into our southwestern counties, and
there continues to be plenty of convection along and north of the
trough axis. However, severe reports have been sparse the past few
hours and SPC mesoanalysis shows the best instability remaining to
our south. Will let the watch expire as scheduled at 10 PM. Will
continue to keep high POPs going overnight as the low continues
eastward, but think the severe threat is minimal as the storms
come into an area that has already been worked over.

UPDATE Issued at 650 PM CDT Mon May 30 2016

Adjusted POPs for current radar trends, as there has been two
bands of convection one near the warm front and another further
south with some mid level warm air advection. The HRRR continues
to do a fairly decent job with the current convection, and will
continue to follow the general pattern of the current bands of
thunderstorms slowly lifting northeast before they are consumed by
the main precip shield coming out with the surface low later
tonight. Included a heavy rain mention for a while this evening as
with weak flow aloft the convection has been moving extremely
slow.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 301 PM CDT Mon May 30 2016

Forecast challenge for the immediate short term will be timing of
convection as well as severe potential given portions of south
central and southeastern ND are in a severe thunderstorm watch.
The HRRR has performed well with band of convection initiating
along a warm front parallel to and south of Highway 2 around
Devils Lake. Will generally follow HRRR guidance through at least
03Z, at which point more widespread activity initiating to our
west will move into the FA.

SPC mesoanalysis currently showing a band of 1000+ J/kg MU CAPE
along and south of the Highway 2 corridor, with the most recent
update extending east of Grand Forks to near the western edge of Red
Lake county. This is also on the nose of theta e ridge extending
up from the south. HRRR has indicated this and expect an
increasing chance that new storms may develop further east along
this line.  However, any convection to the east of what is
currently on radar has very little shear, and the current storms
are barely pushing 30kts 0-6 KM bulk shear. Consequently, although
pulsey, current storms have little movement and have been short
lived. Higher shear to the west will give a better chance for
stronger or severe storms closer to peak heating in one to two
hours.

HRRR brings the more scattered to numerous activity into the Valley
City area by 00Z to 02Z timeframe and this area will have heated
out further by then as the majority of SE ND is currently clear.
Best chances for severe in our FA will likely be Valley City down
through Lisbon and west. SPC will be issuing a severe weather
watch for the majority of the CWA along and south of Highway 2.
The primary threats will be one inch or higher hail and winds of
58 knots or greater, and an isolated funnel is certainly possible
along the warm frontal boundary to the south of Highway 2.

Models indicating clearing occurring in the far west beyond 04Z,
so have began to draw in a dry slot although further redevelopment
will be back in n central and nw ND. Surface low lifts into
southern Manitoba by Tuesday morning and more showery activity
will occur across the far north but should be dry across the
southern third tier of counties. Sfc low then slowly wobbles
across southern Manitoba though the day Tuesday and Tuesday night.

.LONG TERM...(Wednesday through Monday)
Issued at 301 PM CDT Mon May 30 2016

Wednesday will be much cooler as a front moves across the region
anticyclonic flow associated with sfc low in SE MB/SW Ontario
will keep skies cloudy and a chance for scattered showers across
much of the northern half of the CWA. Atmosphere will begin to
dry out from west to  east in the afternoon hours, however late
clearing will hold daytime highs in the upper 50s for the far
northeast.

For Thursday night through Monday...Zonal flow starts out the
period, but as the ridge across the western states starts to build
the flow becomes northwest. Models show sfc low pressure dropping
thru the FA early on, bringing some chances for pcpn mainly Thu
night through Sat. Most of the Sunday and Monday time frame looks
quiet. Temps should be fairly close to normal, or a little bit above.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1148 PM CDT Mon May 30 2016

All TAF sites are VCTS or -RA as showers and thunderstorms
continue to lift northeastward across the area. Lightning has
started to diminish and mostly should be VCSH or -RA by the early
morning hours. Some showers may wrap back around into the KDVL
area late in the period. Cigs on the backside of the low pressure
system are mostly VFR but a few sites in western ND have some
clouds around 2500-3500 ft. Will keep some MVFR cigs going for the
early morning hours and will leave out IFR for now but watch
things closely. All sites should be back up to VFR by afternoon.
Winds will be variable near thunderstorms for the next few hours,
then steady out of the south to southeast. KDVL should see some
northwest winds late in the period as the sfc low pulls eastward.

&&

.FGF Watches/Warnings/Advisories...
ND...None.
MN...None.
&&

$$

UPDATE...JR
SHORT TERM...Speicher
LONG TERM...Godon/Speicher
AVIATION...JR



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