Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 240158
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
858 PM CDT MON MAY 23 2016

.UPDATE...
Issued at 852 PM CDT Mon May 23 2016

Dew points across portions of eastern North Dakota remain in the
50s, mainly along a weak surface boundary stretched from Roseau
County MN to Valley City. A ribbon of higher SB CAPE (500 to 1000
J/KG) just west of this boundary continues to be the area where
weak storms are developing, but an overall lack of deep layer
sheer should keep any storms in check. May see some winds along
outflow boundaries gust into the 40 to 50 knot range but any
severe threat is minimal. Will continue to highlight these areas
with POP grids and general thunder.

UPDATE Issued at 620 PM CDT Mon May 23 2016

Surface based CAPEs this early evening are around 500 J/KG in
the vicinity of Valley City, while mixed layer CAPE is nil.
Radar showing a cell did pop up in S Central Cass County,
however it appears to be isolated in nature and with CAPEs
as low as they are and drier air advecting east, will limit
addition of POPs to southern Cass County into western Clay
County (MN). No other changes to ongoing forecast anticipated
at this time. Note HRRR does pick up on some activity and expands
it...moving into W Central MN through the evening. ATTM believe
this potential is overdone given current instability and
aforementioned drier air moving into eastern ND. Will however
monitor closely per higher res guidance.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 150 PM CDT Mon May 23 2016

Forecast challenges are mainly rain chances and temperatures
through the week. Model differences in surface features and
resulting precipitation coverage leading to less than average
confidence in rain chances.

Forecast area remains under southwest flow aloft with upper low
camped over Sask. Next wave rotating around upper low will swing
into the area later tonight. Drier air has moved into the region
behind departing system with precipitable h20 values .75 inch or
below. With wave and associated weak surface low over the region
cannot rule out some spotty pcpn so have kept low pops going.
minimum temperatures not as mild as last night but still above
average.

As wave rotates northward any pcpn chances should be limited to
the north. With less than ideal agreement between models will keep
pops low. Temperatures will hinge on clouds but with warm column
in place temperatures could get fairly mild.

.LONG TERM...(Wednesday through Monday)
Issued at 150 PM CDT Mon May 23 2016

Better chances for more organized rainfall will be Wednesday into
Wednesday night as upper low begins to propagate eastward into
the fa. Will see a deeper surface low lifting northward into the
area providing more favorable low level forcing. Just where this
low sets up will determine best potential for pcpn but at this
point guidance not in very good agreement.

Surface low lifts into Mb/Ontario Thursday which should lessen
pcpn chances. With clouds and cooler column temperatures will be
much closer to seasonal averages.

Friday to Monday...Active pattern persists for the extended time
frame into the unofficial start of summer...Memorial Weekend. Even
with CHC POPs in every period this will not be a 3 or 4 day rain
event. 500mb southwest flow will bring short wave pieces of energy
to interact with diurnally present instability as PWats remain
around an inch or more through the period. Timing of waves
coincident with peak heating would bring the most wide spread
rains...current trajectories indicate friday night into saturday
morning to be highest CHC of PCPN over the weekend. Max and min
temps right in line with normal for the end of May...mid 70s and mid
50s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 620 PM CDT Mon May 23 2016

VFR conditions through TAF period although did add TEMPO TSRA
to FAR for a cell that has popped up in S Central Cass County.
Not expecting more than ISOLD-SCT storms and only through mid-
evening...however will need to monitor DVL area for development
west of the TAF site as an upper wave moves across the state
after midnight tonight.


&&

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

$$

UPDATE...Speicher
SHORT TERM...Voelker
LONG TERM...JK/Voelker
AVIATION...Speicher


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