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Area forecast discussion 
National Weather Service Grand Forks ND
634 PM CDT Thursday Jul 10 2014

Update...
issued at 628 PM CDT Thursday Jul 10 2014

Main changes were adjusting probability of precipitation through middle evening. Showers and
maybe eventual T confined to southern third of forecast area with current
short wave passage. Northern areas seeing mainly cirrus or clearing so
pulled probability of precipitation as rain chances not expected until approach of cold front passage
later tonight. No other changes.

&&

Short term...(this evening through Friday night)
issued at 304 PM CDT Thursday Jul 10 2014

Thunderstorm chances and severity will be the main forecast
headache for the period.

A lead shortwave currently moving through central ND has brought
plenty of middle level clouds and some radar returns...but there has
not been a lot of precipitation actually reaching the ground so far.
There has been some good lift as the shortwave trough moves
towards the Red River valley...but cape values so far have been
not very impressive...around 500 j/kg and bulk shear values are
better further south over South Dakota. However...moisture transport will
continue to increase this evening ahead of the surface trough axis as
it moves into the County Warning Area. Think that there could be some activity in
our southern counties as the low level jet starts to crank
up...before the shortwave moves well past US into WI. Bumped up
probability of precipitation and quantitative precipitation forecast...but left out a mention of severe at this point.

The main upper trough is still over western Canada...and that will
move into Manitoba tonight. With the strong jet close to the
international border...there could be some storms along the cold
front as it moves into our northwestern counties later tonight.
Again...not much instability available even elevated. Will
continue to keep some probability of precipitation in the north.

The cold front will move into the southeastern County Warning Area during the day
tomorrow as the northern branch upper low heads east into Ontario.
Depending on the exact timing of the front...there could be a fair
amount of destabilization in our southeastern counties before the
front moves through. If NAM cape values of 3000 j/kg verify along
the good convergence zone with the frontal boundary...there could
be some strong to severe storms Friday afternoon before the front
moves off to the southeast. Friday night should be much more quiet
as the front moves out and weak high pressure builds into the
northern plains.

Long term...(saturday through thursday)
issued at 304 PM CDT Thursday Jul 10 2014

Saturday and Sunday...heights will continue to decrease as
reinforcing shortwaves dig the upper low deeper into south central
Canada. There should be one cold front moving in for Saturday
afternoon and night...and another stronger boundary late in the
day on Sunday. Surface winds will be from the west ahead of the front
on Saturday...so there will not be a huge amount of convergence
and surface based cape is not very impressive. Sunday looks even more
stable. Will keep probability of precipitation in the 10 to 40 percent range as these
reinforcing boundaries come down. Temperatures will be near seasonal
averages on Saturday but abound 5 to 10 degrees cooler on Sunday.

Monday...dynamic models remain in good agreement that an unusually
strong middle July upper low will drop across the western Great Lakes.
With the strong cyclonic flow...cold air aloft and time of year
showers are likely especially east of the Red River. Have opted to
not include thunder at this time although its possible with the sub zero
700mb cold pool. Would depend on solar and future forecasts will
resolve that. Current guidance suggest record low maximums across
our County warning forecast area.

Tuesday...deep north flow surface and aloft gradually relaxes with
attendant brisk north flow. Quite cool despite increased solar as
higher heights/thicknesses slow to move in behind departing low.
Another unusually middle July day. Outside of some lingering -rash 00z
- 12z Tuesday expect very low risk of precipitation. Plan to keep
with current dry forecast during the day.

Wednesday and Thursday should remain precipitation free with each
day a little warmer. Return flow out of cool high and slowly
increasing thicknesses suggest warming to near climatological normal
likely by end of period.

&&

Aviation...(for the 00z tafs through 00z Friday evening)
issued at 628 PM CDT Thursday Jul 10 2014

VFR conditions expected through the period. Will see some VFR ceilings
across the southern third along with some rain showers/isolated T but VFR
visibility. Farther north will not see any precipitation chances until later
tonight when cold front approaches. Cold front should reach dvl
in the early am hours...valley middle late morning and through the
east by evening.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

Update...voelker
short term...Jr
long term...Jr/ewens
aviation...voelker

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