Area forecast discussion
National Weather Service Grand Forks ND
1155 PM CDT Thursday may 23 2013
Update...
issued at 1155 PM CDT Thursday may 23 2013
Temperatures were falling faster in the east than expected. So have
decreased temperatures east for morning by a couple degrees.
Update issued at 959 PM CDT Thursday may 23 2013
Water vapor loop indicated northwest flow across the area. An upper
low was located over northeast man and will move southeast. Low not
expected to affect the area as upper ridge shifts east overnight.
Dewpoints were relatively high over southwest and far northwest
zones. Elsewhere dewpoints fell into the 20s today and were beginning
to rise with sunset. Will keep low temperatures for tonight as is. Backed
off on winds overnight mainly in the eastern zones.
Update issued at 659 PM CDT Thursday may 23 2013
Upper level ridge axis was over the central Dakotas and will move
into the eastern Dakotas tonight and Friday. Higher precipitable water
over Montana/Wyoming will shift east tonight and Friday.
Tweaked low temperature for tonight. A degree lower in the west and degree
higher in the east. Going forecast os reasonable.
&&
Short term...(this evening through Friday night)
issued at 330 PM CDT Thursday may 23 2013
Forecast challenge concerns temperatures and low end precipitation chances
through the period. Overall models in reasonable agreement and
will use blend.
Surface high pressure will shift east into Minnesota overnight. Weak
return flow will set up however with sky clear and relatively low
dewpoints region will see a cool night. Not be surprised if a few
areas across the far east under high get some patchy frost.
After cool start will see some modest warm advection which will
help temperatures recover close to today. Mixing to increase as
well as clouds ahead of weak short wave. Surface forcing remains
to our west however maintained inherited probability of precipitation as lowering
condensation pressure deficits and weak isentropic lift moves into
forecast area middle to late afternoon.
Best potential for any precipitation will shift into Minnesota overnight. From
late afternoon into the overnight instability minimal so fairly
low confidence on lightning however maintained isolated mention.
Slightly warmer column and temperatures will hold temperatures up
with no frost potential.
Long term...(saturday through thursday)
issued at 330 PM CDT Thursday may 23 2013
The first half of upcoming Holiday period looks to feature more
clouds than sun...below average temperatures and spotty precipitation
chances. With lack of instability and surface forcing/moisture axis
to our west not a great deal of confidence in any organized precipitation
through Sunday.
Models in general agreement on overall theme for next
week...chances of showers/thunderstorms throughout the period. While exact
timing of features are different...models indicating an
increasingly southerly fetch of Gulf moisture in to the plains.
Limiting factor for northern tier will be likely convection in the
Central Plains...which will limit some moisture availability in
our area. Also timing of the departure of an upper ridge early in
the period...which models are still struggling with. Upper pattern
should switch to a SW flow pattern by middle week...if not sooner.
&&
Aviation...(for the 06z tafs through 06z Friday night)
issued at 1155 PM CDT Thursday may 23 2013
VFR conditions expected for tonight and much of Friday. Fog
loop/surface observation indicated cirrus clouds spilling into the western
zones this evening and expected high clouds to shift east overnight.
Ceilings should lower from the west as system approaches forecast area
on Friday. Some MVFR conditions possible in western zones by late Friday
afternoon. Also few light showers possible late in the period.
&&
Hydrology...
issued at 959 PM CDT Thursday may 22 2013
River flood warnings remain in effect at Neche along the Pembina
river. Other river flood warnings remain at Pembina...Drayton and
Oslo on the mainstem red...as well as Hallock...Grafton...Dilworth
and Sabin.
Fargo...Minto and Walhalla are to remain below flood stage and the
warnings at those points have been cancelled.
The Park River at Grafton appears to have crested and the stage is
currently below 15.5 feet and continues to fall.
Areal flood warnings remain in effect for Pembina...eastern
Cavalier...and Walsh counties. The main surge of water is now into
central Pembina and Walsh counties...and will continue to move
toward the Red River. Water levels across this area should gradually
decrease over the next few days with little additional rainfall
anticipated.
A Flash Flood Watch remains in effect through Friday afternoon for
areas downstream of the Renwick dam on The Tongue river. Water
remains very high at the dam site and is being held back by a
constructed earthen levee on top of the dam structure. At this
time...officials note the temporary levee on top of the Renwick dam
remains stable and will still be monitored. Otherwise...Lake Renwick
has been slowly receding over the last 24 hours. Also...water has
stopped flowing over the emergency spillways at most of the
retention dams west of the Renwick dam.
&&
Fgf watches/warnings/advisories...
ND...Flash Flood Watch through Friday afternoon for ndz008.
Minnesota...none.
&&
$$
Update...hoppes
short term...voelker
long term...speicher/voelker
aviation...hoppes
hydrology...hoppes
