Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
948 am CDT Friday Aug 22 2014

Update...
issued at 948 am CDT Friday Aug 22 2014

Showers which have persisted through middle morning over portions of
northwest Minnesota will slowly shift eastward into the Lake of
The Woods through early afternoon. Else...showers moving from
central ND towards eastern ND should diminish through the late
forenoon... with scattered deep convection expected to redevelop
later this afternoon. No sig changes to forecast package expected at
this time.

&&

Short term...(today through saturday)
issued at 403 am CDT Friday Aug 22 2014

With the upper air pattern, the GFS and European model (ecmwf) were similar and
faster than the NAM and the Gem. NAM was the slowest model. At the
surface, the European model (ecmwf) was the slowest solution of the set. Will prefer
the European model (ecmwf).

Water vapor loop indicated a short wave trough over the Montana/ND
border. Short wave trough forecast to move into southern man this
afternoon. Will have scattered precipitation over the northern zones for
today.

Also water vapor loop indicated upper level low over the Pacific
northwest is forecast to amplify today, then weakens a bit. Trough
moves out of The Rockies and takes on a negative tilt and
intensifies again after 72 hours.

Also upper level low over the Desert Southwest will move into the
northern plains Sat/Sat night/sun and produce another round of
precipitation. 700 Theta-E ridge also moves over the area. Precipitable
water rises to to over 2 inches by Sat. Will add threat of heavy
rain for Sat afternoon and Sat night.

Long term...(saturday night through thursday)
issued at 403 am CDT Friday Aug 22 2014

/Mon through Friday/
the long range models are somewhat in agreement for next week with a
changing upper level pattern...however the GFS is faster with a
sharp short wave crossing the northern plains middle week. It is also
much drier with the European model (ecmwf) keeping precipitation across the southeastern
County Warning Area. Dry probability of precipitation for the majority of the County Warning Area (most of ND and northwest mn) on
Monday/Tuesday seem reasonable with upper pattern keeping best energy from
Central Plains into the Great Lakes. By Wednesday/Thursday the GFS builds a
ridge over Saskatchewan while the European model (ecmwf) is a bit further west with
the ridge axis and also less amplified. Day six showing some light
precipitation over area with the northwest flow pattern becoming dry at
night...which seems reasonable for northwest upper flow pattern. For late
in the week the GFS continues to amplify the upper ridge over the
northern tier and mb...keeping things dry...while the European model (ecmwf) has more
zonal flow with waves moving across southern Canada. Will lower inherited
chance probability of precipitation for the end of the week. Significant difference in model
solution begin on Friday...with the GFS showing a strong low bringing
precipitation to the area and the European model (ecmwf) continues the zonal flow
pattern...giving ME very low confidence in solution for day 7.

&&

Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 701 am CDT Friday Aug 22 2014

IFR to MVFR conditions were across the forecast area mainly due to
low ceilings except over southeast ND where visibilities have lowered to
1/4 mile in the last hour. Fog loop indicated blow off from
showers/storms along the Nova Scotia/South Dakota border will overspread the southeast
zones shortly. Expect visibilities to increase over the next couple
hours. Ceilings should slowly rise to the VFR category this afternoon.



&&

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

$$

Update...gust
short term...hoppes
long term...speicher
aviation...hoppes

National Weather Service Glossary of Abbreviations