RISK OF SERIOUS COLD FOR MIDWEST INCREASING FOR WEEK 2
SHORT TERM (next 60 hrs ) MARCH 29-30
Over the Western CONUS that Huge Low has developed as forecasted and is bringing heavy spring snows to central and northern Calif mtns ... northern NV far eastern OR much of ID.... WY and western and central MT. As the Low moves east significant snow will rains will develop over the Plains
.
As this Low comes east it will pull up REALLY warm air into eastern COL.... eastern WY eastern MT as well as western and central SD... western & central NEB ... western and central KS and OK and western Tx.... some places will see temps in the M and U 80s this afternoon ... but it will be only 1 day HOT interval as the rains reach the Plains Wednesday night and Thursday .
On the 29th significant to heavy rains will fall over most of the central and Upper Plains....60-70% coverage of 0.25 to 2.00"... much less coverage over the Lower Plains.
On the 30th the Best rains will fall N to S ... from all of MN ... all of IA all of MO eastern OK and ARK eastern TX into the Delta.... 0.25 to 2.00" of 75% coverage. Some of the rain May change to snow over the Dakotas.
MEDIUM RANGE MARCH 31 - APRIL 4
On the 31st into the 1st the rain shield will move into the WCB with more heavy rains and good coverage.... into the Delta ....60% coverage of 0.25 to 2.00"
On APRIL 2he rain shield will move into the ECB with more moderate rains and good coverage........70% coverage of 0.15 to 1.00"
DAY 3 FORECAST RAINFALL
http://www.hpc.ncep.noaa.gov/qpf/fill_99qwbg.gif
DAY 4-5 RAINFALL
http://www.hpc.ncep.noaa.gov/qpf/95e00p48iwbg_fill.gif
WHAT COULD GO WRONG There is strong model agreement on this front and the Low moving east thru the Plains and Midwest. Its hard to see what could go wrong here.... This is going to be a slow moving system
WEEK 2 APRIL 5 - 10
The midday WED American model continues to develop a Historic cold air outbreak for eastern half of the CONUS after April 4... and according to midday models the cold pattern stays in place right through the middle the month.
Again I want to emphasize that according to the midday American model the heart of the cold air does NOT affect the winter wheat areas . Instead the cold air is pretty much confined to the eastern portions of the Upper Plains as well as entirely eastern half of the US which in this case will be defined as east of the Mississippi River.
There is some concern that the American model here it midday is overdoing the cold pattern... but even if that is the case there is increasing concern that a pattern of significantly below Normal temperatures will dominate the eastern half of the US through the middle of the month. And given how wet the ground conditions are over many locations in the Midwest (and will be after this week) ... a prolonged interval of Below and Much below Normal temperatures is not really desired at this point.
The key to the idea of extreme cold as shown by the midday American model for early and mid-April i are TWO Features. First the development of the large Ocean storm near Newfoundland which is often referred to in the weather business as a "50-50 Low" . This term refers to strong Low pressure which is located near 50° north latitude and 50° west longitude which is also the location of Newfoundland Canada.
Second the development of a Blocking High over Greenland in the Jet Stream. As you can see by this map the Day 6 American model develops a huge low pressure area at or near Newfoundland... the 50/50 Low.... and this in turn increases the Blocking High pressure area over Greenland.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_500_144s.gifThe appearance of BOTH of these features... the Blocking High over Greenland and the 50-50 Low... has always been and will always be a strong indicator that the eastern half of the CONUS is likely to go into a colder than normal pattern... and it really does NOT make a difference if this sort of configuration in the Jet stream occurs in December or June. Both of these features together
(if in fact they do occur
) will always been about a pretty deep trough over the east glass and a cold pattern.
day 9 http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_slp_216m.gif day10 http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_slp_240m.gif
day 12 April 9 http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_slp_288m.gif
day 14 April 14 -- heavy rains over Delta and Tenn MIGHT move into the ECB
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/images/gfs_slp_312m.gif
WHAT COULD GO WRONG; We have two scenarios....Let me emphasize that in order to see this *** POSSIBLE ***historic cold pattern that the Midday Wed American model is depicting ..... we need to see both features develop by April 2 -3. (The big Low near Newfoundland Canada AND the BIg blobking High in he Jet stream) . If only one of these features develop then we end up with a cool/ cold pattern but nothing too extreme.
weather update #4 MARCH 28 -- More RAINS then POSSIBLE record cold
