ECMWF Weekly Maps

January 19, 2015

It’s Monday, and 4 fresh weekly maps just came in.  You know the routine; 1 map for each week of the ECMWF monthly run last night.  Each map shows the height anomaly (in color) at the 500 millibar level (around 18,000′).  They include the average height of all ensemble members as well.

Week 1:  We already know what’s coming, a very strong and warm upper-level ridge the end of this week and early next week.  Move along folks…nothing to see here.  Actually that’s not quite true.  Sunday or Monday could be spectacular anywhere above 1,500′ with warm temps in the 60s and maybe even some 70s.

500za_week1_bg_NA

Week 2:  Last week of January.  Ridge moves a little to our east, or actually develops over there.  We may see some rain at times, although it would still be mild rain.  This takes us to the 1st of February.  Looking at the daily maps on the control run, there would be some mountain snow later in the period here.

500za_week2_bg_NA

Week 3:  First week of February.  A bit different, the ridging flattens and heights go normal or a little below.  Looks much wetter to me.  Interesting upper-level high developing over Western Alaska may or may not play into to the forecast.  I haven’t seen the control run or even specific days of the ensembles to see what’s going on during this period.  Nothing too exciting can happen at this time since I’m on vacation for almost a week and “off-continent”.

500za_week3_bg_NA

Week 4:  Through mid-February and Valentine’s weekend.  Ridge wants to return to where it has been much of the winter, over Alaska and the west coast of North America.  Back to drier than normal.  The end of this period is about the time where the increasing sun angle and longer days can start seeing the inversions break a little.  A ridge over us on February 15th can easily give us 55 degree days without too much effort.  That said, the control run has the ridge slightly farther west a few days after Valentine’s Day (only 29 days away!) and a late season arctic blast on the 16th.  I’ll sneak one “illegal” pic showing that into here (shhh!):  eps_m_z500a_c_noram_59  Then ridging comes right back over us 17th-20th.  That would be very similar to what we saw in November and early December.

500za_week4_bg_NA

To wrap it up, maybe a wet period of some sort coming up around 8-14 days from now, then back to drier again.  No sign of a cold/snowy pattern for lowlands, or even foothills for that matter.

Chief Meteorologist Mark Nelsen