A Brief Post

October 17, 2006

I’ve been a but busy with our brand new weather center this evening, so you get a short post.  You’ll see the new digs in a couple weeks.

Simple forecast for tonight…FOG.  High dewpoints (above 40 deg), plus moist ground and clearing skies spells fog on an October night.  As it SLOWLY breaks up tomorrow, expect high clouds to thicken ahead of the next weather system.  Overall not a lot of sun.  Rainy Thursday as the system drags by to the north, then strong upper-level ridging mentioned in last night’s post appears to take over starting Friday.  Could be a nice east wind episode Saturday & Sunday, which makes for a very nice weekend forecast.  ECMWF is quite a bit weaker with the ridge and allows a system through early next week.  I’m discounting that…for now…Mark

Ridgey Weather

October 16, 2006

Junk2Showers dying down late this afternoon…and not nearly as much convection today as I expected.  BUT, that was a nice little squall at 2-3am wasn’t it?  It woke me up as hail was pounding against the northwest facing windows.  Those rain totals to the left are ending at 5pm Monday.

The BIG picture is one of upper-level ridging redeveloping through the next 7-10 days just west of the North American coastline.  Each model run is slightly different of course and the devil is always in the details.

I finally broke down (sobbing) and added rain to Thursday’s forecast since it appears one last weather system moves over the top of the ridge and plummets down into the Rockies, giving us rain as it passes over.  I knew this was a threat while forecasting the last 2 days but I was in denial.  After that it’s back to ridging for the weekend with nice offshore flow.  Of course about 5 days ago it looked like the next 2-3 days would see nice offshore flow and sun too, so hopefully models will settle down a bit and do a better job over the next week.

October is the foggiest month at PDX (on average), so moist ground & high dewpoints the next couple of days combined with any clearing at night should lead to some fog each morning/midday.  We aren’t quite up to the time of year where the fog can get stuck in the valleys all day.  That doesn’t happen until around mid-November…Mark

Sunday Afternoon Extra

October 15, 2006

Another day of slogging through weather maps…amazing that I get paid to do this…

Nice cold front today, a bit refreshing, but I’m already tired of the gloom and ready for more sun.  Cool air behind front shows up nicely on visible satellite loops this afternoon, it moves in overnight and could provide us with enough instability for an afternoon thunderstorm tomorrow.
Still messy long range maps, although they’ve come together just a bit.  General idea is for ridging overhead through the next 7 days, BUT, 2 systems move by to the north and just clip us as they go by.  One on Thursday and another next Sunday.  I’ve left rain out of the forecast for now, even though GFS is very insistent on bringing some light rain inland Wednesday night and Thursday.  These systems going by to the north also keep high pressure from developing strongly at the surface to our north too, so forget about any significant east wind.  And with moisture leftover from the rain, we could have some fog/stratus issues Tuesday/Wednesday mornings/midday…Mark

Saturday Night Special

October 14, 2006

I’m working this weekend for Drew, so I’ll blog…but only briefly.  I have to reserve my energy for another 6 days of weathercasting.

Nice cold front approaching the coastline tonight.  Looking at the satellite picture it doesn’t look THAT impressive, but both NAM & GFS are very wet for tomorrow.  Looks to me like a 4 hour shot of pretty steady rain (maybe .50") between 9am-1pm.  Showers for Monday, and with low lifted index and some CAPE, I threw a thunderstorm into the forecast too.  That’s by no means a certainty, but it should be a bit unstable.
Ridging develops Tuesday and turns our windflow back to offshore, so the sun will return along with dryness too.
If you’ve been looking at long-range maps, you’ll notice a HUGE amount of disagreement today on the forecast beyond Thursday.  But as of the 00z GFS run, the ECMWF is the only model still showing another system dropping by to our north/east next Friday.  GFS & Canadian now have solid ridging overhead, so I kept the forecast dry through next weekend.  The GFS in fact shows no organized fronts or disturbances for the next 12 days after Monday’s showers end.  Hard to believe…we’ll see…Mark

A Job Shadow’s Perspective

October 13, 2006

Hey everybody! Mark’s letting me post tonight so I thought I would talk about the weather center real quick. Its really complicated in here, there are a bunch of computers.(…of course) They are all routed to do a bunch of different things and its really cool. He even had me press a button for him when he was in another room, my first big task. Don’t laugh at that. As for the weather its a pretty nice system coming in Sunday-Monday. Could be upwards of .75 in the city, of couse that would mean areas in the Coast Range and against the Cascades would see even more. After that sadly,(though Mark says otherwise about the "sad" part) its back to more ridging. Lets hope the models switch to more cool weather soon, wouldn’t surprise me!

Derek Hodges

Mark’s Update:  Derek behaved very well tonight.  Lots of geeking out and no yelling during the weathercast!  By the way, this is how our internships/job shadows work:  Job shadows are a one-day event for a high school student.  An internship is several months long and limited to college students who are majoring in meteorology or atmospheric sciences.  If you’re interested and fill one of those descriptions, send me an email.
Weather maps are sure looking "el nino-ish"  to me, although I’ve never noted a connection between October weather and the following winter.  Either way after Sunday-Monday’s rain, it’s back to ridging and warmer temps again.  Poor Derek and the rest of you are just going to go crazy aren’t you?  Enjoy the big "storm" Sunday!…Mark

An Early Post

October 12, 2006

I’ve got forecasting all done with now, so I figure why not just blog away early.  As of 4pm temp is up to 75, so I’m guessing the high will be about 77.   (Update at 9pm:  High was 78 at PDX just after 5pm)

Weak onshore flow tomorrow should drop us just a few degrees, then a better push for Saturday should easily drop us closer to normal (mid-60’s).

A very juicy coldfront for Sunday and a following wave for Monday along a "quasi-arctic front" (like that?) should give us a good soaking…maybe .50-.75".  That front, along with the change to north and northeast wind, moves through on Tuesday.  After that it’s all dry with a much cooler Canadian airmass over us the rest of the week.  This early in the season we’ll see a similar effect as we would in early March;  brief cooling and then a warmup as we mix some downslope wind with cool air through the Gorge.  We really have to wait until after Halloween to see a good cold east wind.  This pattern sure is interesting though…just 4 weeks from now I’d be excited about possible snow and sunny days in the mid 40’s at best.  One thing is pretty certain…after a shot of rain, we’re heading back into dry weather, but a bit cooler…Mark

Warm, Then Cool

October 11, 2006

Allright, I win last night, but you 80 naysayers won today.  We were warmer overnight, but could only reach 76 at PDX today.  Obviously that 80 at the end of September will be the last of the year, especially looking at next weeks maps.

Ridging GRADUALLY weakens overhead the next 3 days, and by Saturday we have weak onshore flow.  That can make for a tricky forecast since any low clouds that develop this time of year are very hard to break up with the weak sunshine.

Nice cold front later Sunday and Monday should give us a good soaking.  Maybe up to .50" even in the lowlands.

Evening models have come around to a developing upper-level high over the Gulf of Alaska next week linking up with ridging developing again well offshore.  That digs a surge of cold air south out of Western Canada down over us.  Just 4 weeks from now I’d be thinking we could be in a snow pattern, or an early season arctic air outbreak.  But this time of year it should just turn chilly and breezy once the east wind arrives by midweek.  I’m discounting the -9 850mb temp to the GFS’s usual zeal for cold air in the long range.  A -7 to -8 after Halloween is cold enough to give us snow if we have moisture…Mark