Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 161504

Area Forecast Discussion
National Weather Service Grand Forks ND
1004 AM CDT Wed May 16 2018

Issued at 958 AM CDT Wed May 16 2018

Front continues to slowly sag southward this morning. Current
SFC analysis shows its position from near Shooks in the east to
Buxton to New Rockford in the west. Expectations for winds and min
RHs along with temps have not changed for today with a wide
spread range of Max temps from mid and upper 80s in the south to
low 70s in the north.


.SHORT TERM...(Today and tonight)
Issued at 326 AM CDT Wed May 16 2018

Main short wave and associated sfc low which produced scattered
t-storms in southern Manitoba Tuesday evening is moving east-
southeast with showers toward Thunder Bay Ontario region. A cool
front will drop south behind this system into NE ND and NW MN
during the course of the morning reaching near Highway 2 midday
and then toward the Fargo area late afternoon. Ahead of this front
will be very warm temperatures as winds go westerly while cooler
air will drop in behind the front as winds turn northeast to east.

The pressure gradient with the front isnt strong so fortunately
winds will not be strong...more in the 10-15 mph range...few
higher gusts north and south of the front with light winds within
the frontal zone. Highs today will reach the upper 80s SE ND/S RRV
with 70s along the Canadian border.

Main short wave and lift will be well east of the area this aftn
but with weak sfc boundary west into the mid RRV to near Duluth at
mid afternoon there may be enough instability for an isold
shower...though latest HRRR/RAP indicate a bit better chc toward
Duluth than in our area. So for this reason did go along with DLH
and kept fcst area dry with this boundary this aftn.

Frontal boundary will hang up in the southern fcst area tonight
and then start to move back north late tonight. Mid level moisture
spreading north over the frontal zone will create increasing
clouds and the risk of showers mainly after midnight across
southwestern Manitoba into northeastern North Dakota and
northwestern Minnesota. Kept pops mostly in this zone overnight.

.LONG TERM...(Thursday through Tuesday)
Issued at 326 AM CDT Wed May 16 2018

Thursday will bring our next chance for widespread rain as a surface
low moves into the Dakotas. Thunderstorms will be possible with the
question being how far north and east the thunderstorms could be.
The best chances for thunderstorms will be the southern and central
Red River Valley and to the west in North Dakota. This is the area
that after daytime heating could end up with significant CAPE. Model
forecasts have MU CAPE values generally in the 500 to 1000 J/kg
range in the Red River Valley with larger amounts near 1500 to 2500
J/kg farther west in North Dakota. As with earlier model runs the
NAM is providing more CAPE than the GFS which is tied to more
widespread stratiform rain in the GFS. Bulk shear looks best in
northern, central, and western North Dakota. So based on current
model guidance the best chance for strong thunderstorms would be
west of the Red River Valley on Thursday.

Friday CAPE will be much lower so there is less of a chance for
thunderstorms but additional rain is expected through Friday night
as a cold front moves across the Northern Plains. Total rainfall for
this event, combined with Thursday`s rain, could range from half an
inch to over an inch and a half in some areas. Dry areas, especially
near the Canadian border, should get some much needed rain.

Cooler, dry weather Saturday with highs in the low  to mid 60s under
high pressure behind the cold front. A new warming, but dry, trend
begins Sunday with temperatures warming into the mid to upper 70s
early next week. The next chance for rain comes on Tuesday but there
is still model disagreement on this pattern so timing and amounts
still uncertain.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 641 AM CDT Wed May 16 2018

VFR thru the pd. Issue today will be wind shift as a cool front
drops south through the area. Winds will go from southwest to west
to northwest then north and finally end up northeast behind it.
DVL,GFK, TVF, BJI TAF sites will see this wind shift during the
morning/midday with Fargo a tad later. Speeds mostly 10-15 kts but
ocnl gust 20 kts or so psbl. Likely mid level cloud cover
development tonight with a few showers in NE ND/NW MN after




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