Area Forecast Discussion
Issued by NWS Grand Forks, ND

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514
FXUS63 KFGF 251448 AAA
AFDFGF

Area Forecast Discussion...UPDATED
National Weather Service Grand Forks ND
948 AM CDT Wed Apr 25 2018

.UPDATE...
Issued at 948 AM CDT Wed Apr 25 2018

Issued a special weather statement regarding fire weather concerns for
this afternoon and early evening. Minimum humidities in the 20s
combined with gusty winds will create near critical fire weather
conditions in portions of northwest MN. Otherwise no significant
changes to the forecast at this time.

UPDATE Issued at 701 AM CDT Wed Apr 25 2018

Taking a second look at winds, and it seems they will be high
enough to cause fire weather concerns in the northern Devils Lake
Basin and northern RRV this afternoon. Issued Red Flag warning.
Bumped up POPs a bit for tonight as it seems that high resolution
models are coming into some better agreement on showers along the
cold front, but amounts continue to look very light.

&&

.SHORT TERM...(Today and Thursday)
Issued at 329 AM CDT Wed Apr 25 2018

Winds will be the main issue for the period.

Surface high pressure over the CWA this morning will move
southeastward and a trough will move in from the northwest in
response to the vigorous shortwave that will dig into eastern MT
today. The pressure gradient will tighten nicely and winds will
become rather breezy, particularly over the northwestern counties.
There should be a decent amount of mixing, up to at least the
850mb level where speeds are in the 30 to 35 kt range. Wind
forecast was too low yesterday, but we will not have the cold air
advection today that we did then. Another damper is high clouds
moving in ahead of the shortwave, which could decrease mixing a
bit. At this point, do not think we will hit advisory criteria
but may have to watch winds for fire weather concerns. Winds will
briefly decrease this evening then pick up again to above 20 kts
in some areas as a cold front begins to push into the CWA.

The shortwave trough and front moving through the Northern Plains
tonight and tomorrow will also bring a chance for some rain. High
resolution models have some fairly sparse QPF moving into our
northwestern counties by the evening. There is some decent
forcing, but moisture is somewhat lacking and think that any
amounts will be a few hundredths at most. The chance for rain will
quickly push eastward into our MN counties by Thursday morning
before tapering off completely as high pressure builds into the
area.

Temperature wise, warm air advection today and good mixing should
help boost readings into the 60s again, although will have to
watch high clouds in case they impact insolation more than
expected. Cold front moving through tonight will drop the northern
counties into the 30s, but the south could stay in the low 40s
with a later frontal passage and more mixing. Strong cold air
advection will offset sunshine on Thursday after the clouds and
precip clear out. This will keep temps in the 50s and with winds
things will be rather blustery.

.LONG TERM...(Thursday night through Tuesday)
Issued at 329 AM CDT Wed Apr 25 2018

Quiet weather is expected for the first half of the extended
forecast as an upper level ridge builds over the central CONUS from
late Thursday and into the weekend. As this occurs, surface high
pressure will gradually move to the southeast of the region by
Friday afternoon while broad southwesterly flow over the Rockies
will allow for weak lee troughing Friday and into Saturday. This
synoptic set up will allow for strong southerly winds through the
Plains Saturday and into Sunday. This advection of warmer air will
bring afternoon highs in the 70s for Sat/Sun and perhaps low 80s for
a few locations on Monday. Weak moisture advection during this
period should allow afternoon relative humidity values to remain in
the 30-40% range and minimize the fire weather danger.

Model guidance is in relatively good agreement of a shortwave trough
propagating into the northern Plains region Sunday night and into
Monday. As an associated surface low deepens and moves northeastward
across the region rain chances will increase across eastern North
Dakota for Sunday afternoon and across the River Valley and
northwest MN for Monday afternoon. Most guidance suggest the
presence of at least a few hundred J/kg of MUCAPE, so a few rumbles
of thunder will be possible both days.

As the low progresses to the northeast into southern Ontario Monday
night and into Tuesday the attendant cold front will push through
and bring in cooler air for Tuesday with highs in the 60s and low
70s expected.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 701 AM CDT Wed Apr 25 2018

High clouds moving in and VFR conditions throughout the period.
Winds will ramp up later this morning and into the afternoon from
the southwest. Highest will be at KDVL, where there could be gusts
up around 30 kts. Winds will shift to the north tonight as a cold
front moves through, starting in the evening at KDVL and not
shifting until close to the end of the period at KBJI. Speeds will
continue to be breezy, with gusts above 20 kts.


&&

.FIRE WEATHER...
Issued at 948 AM CDT Wed Apr 25 2018

UPDATE: Winds have been trending a bit higher, so issued a Red
Flag Warning for the upper Devils Lake Basin into the northern
Red River Valley and Special Weather Statement for portions of
northwest Minnesota.

After light winds this morning, speeds will increase
out of the southwest, particularly across northeastern ND. The
winds will be right around the 20 mph mark, and some higher gusts
are not out of the question. Temperatures rising into the 60s and
dew points in the 30s and even upper 20s will drop afternoon
relative humidity values into the 20 to 30 percent range. This
puts us borderline for Red Flag criteria, and if winds are higher
than expected, we could be definitely in the range for fire
weather headlines. On the other hand, high clouds moving in could
put a damper on mixing and could keep RH values slightly higher
than what we have going. With uncertainty, will hold off on
headlines for now and monitor the incoming rapid refresh/high
resolution models for the next few hours. Will include critical
fire conditions wording in the FWF and HWO for now, and reevaluate
for the possibility of a Red Flag a bit later.

&&

.HYDROLOGY...
Issued at 329 AM CDT Wed Apr 25 2018

Moderate flooding continues along the Goose River at Hillsboro, the
Snake River at Alvarado, and the Red River at Oslo. Water levels at
Hillsboro and Alvarado are slowly declining and expected to drop
into minor flood stage by the end of the week. Hillsboro will have
to continue to be closely monitored for any further water rise
related to log jams. Oslo is expected to remain in Moderate flood
stage through the remainder of the week.

All other locations are at or below minor flood stage and are
expected to follow the water level forecasts. Grand Forks is
reaching its forecast crest and should begin to gradually recede in
the coming days while Warren and Enderlin are both expected to drop
below minor flood stage in the next 24-48 hours.

Although the current forecast has precipitation chances for
Thursday, rainfall is not expected to be substantial enough to cause
an impact to current or forecast water levels.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...Red Flag Warning from 1 PM this afternoon to 7 PM CDT this
     evening for NDZ006>008-014>016-054.

MN...Red Flag Warning from 1 PM this afternoon to 7 PM CDT this
     evening for MNZ004-007.

&&

$$

UPDATE...BP
SHORT TERM...JR
LONG TERM...AM
AVIATION...JR
FIRE WEATHER...BP
HYDROLOGY...AM



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