12z RPM Forecast for 5pm Today
Here is the 5pm forecast for today from WSI’s 4km RPM model (the same thing we use on the air). Looks like it did pretty well. When we saw this yesterday we put flurries in the forecast for the Cascades late this afternoon and evening. That’s exactly what is happening. Great forecast by a mesoscale model. A few showers have even appeared over the lowlands, although very light. So what does it show for Sunday morning? Here:
18z RPM Forecast for 8am Sunday AM.
Nothing too significant. On later images the snow over the Cascades stays put…it’s upslope flow into the east side. But cloud cover coming over the Cascades moving west out over the Valleys could produce some snow showers. That’s it, then it’s on to dry and COLD! More later…
I notice around Wed night the 00z WRF-GFS shows a major east wind through the Gorge.
http://www.atmos.washington.edu/mm5rt/data/2009120500/images_d2/slp.126.0000.gif
Has it shown much in the way of moisture yet?
Yep… Just what I was mentioning. Could be fun, and that will only reinforce the deeper cold which will be firmly entrenched east side. More so than models show, so I would not be surprised if temps Wednesday-Friday as colder or as cold as Monday.
Yes! I like the sound of that!
moisture?
Moisture is the toughest call…. Doesn’t look likely, but who knows beyond 6 days.
Wow. I found 56 knots on the one I clicked on and I didn’t even map the storm. Daddy needs a new pair of shoes!
Lucky!
How has the 00z turned out so far?
East winds much stronger on this 00z WRF-GFS run. Looks like 10-12mb.
Sounds like Crown Pt weather coming up.
Surface gradients
As of 9 PM|Current|Hourly Change
[Gorge]
PDX-DLS: -0.2mb | 0.4mb Increase – Switched to offshore
TTD-DLS: -0.8mb | 0.3mb Increase
[Fraser River Outflow]
BLI-YWL: -8.2mb | 0.3mb Increase
Thanks Rob. What does the Fraser gradient typically get to in a good blast?
-12mb+
You’re welcome.
We are getting there!
Rob it truly frightening and impressive how well you know your gradients. Bravo!
Thanks…. I’m not ready to give a gradient forecast just yet. 8mb minimum though….
doesn’t paste well. those are knots here is the site
http://www.ndbc.noaa.gov/
Thanks. Could not find anything over 40 knots but did find a barometer of 28.36. Wow! Cool site.
I can remember 1 or 2 times in the past 25 years that we received no frozen precipitation on the ground during an arctic airmass both at the beginning and exit of the cold air. One time was close because I think we had some flurries but nothing accumulated. Could this be another one of those? I would generally say 5% chance of that happening but it looks right now like 30% chance of that happening this time. I definitely hope that we get something though before the end of next week
Naw, we get slammed before this is over. I just feel it. Plus the models keep extending the cold and the eventual pattern after 5-6 days keeps developing. The Northern upper level flow looks to continue a while. Nobody (Met’s) is going to forecast real cold (sub freezing highs) around here beyond 4-5 days our no matter what model shows what.
I sure hope so PaulO!
On a different topic: I wonder what wind speeds ar with the monster low moving across the Aleutians right now. Any reporting stations up there?
http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?wv_common_full+12
* are
here’s one at random
MM DD TIME
(AKST) WDIR WSPD
kts GST
kts WVHT
ft DPD
sec APD
sec MWD PRES
in PTDY
in ATMP
°F WTMP
°F DEWP
°F SAL
psu VIS
nmi TIDE
ft
12 04 6:50 pm SE 35.0 46.6 26.6 13 9.5 – 29.37 +0.03 41.9 40.3 – - – -
12 04 6:20 pm – - – 29.9 13 9.7 – 29.35 – - 40.5 – - – -
12 04 5:50 pm ESE 36.9 46.6 31.5 14 10.2 – 29.35 -0.02 41.4 40.1 – - – -
12 04 5:20 pm – - – 28.9 14 9.5 – 29.34 – - 40.5 – - – -
12 04 4:50 pm ESE 38.9 – - – - – - – 41.4 – - – - –
12 04 4:20 pm – - – 32.2 13 9.9 – 29.33 – - 40.5 – - – -
12 04 3:50 pm ESE 40.8 54.4 31.5 13 9.8 – 29.34 -0.10 41.2 40.5 – - – -
12 04 3:20 pm – - – 30.8 14 9.8 – 29.34 – - 40.5 – - – -
12 04 2:50 pm ESE 44.7 54.4 – - – - 29.36 -0.12 41.2 40.3 – - – -
12 04 2:20 pm – - – 29.9 13 9.5 – 29.37 – - 40.5 – - – -
12 04 1:50 pm ESE 42.7 54.4 24.9 14 9.2 – 29.39 -0.11 40.6 40.1 – - – -
12 04 1:20 pm – - – 27.2 13 9.1 – 29.41 – - 40.5 – - – -
12 04 12:50 pm ESE 40.8 50.5 27.2 13 9.3 – 29.44 -0.11 39.9 40.5 – - – -
12 04 12:20 pm – - – 29.5 14 9.7 – 29.46 – - 40.6 – - – -
12 04 11:50 am ESE 40.8 54.4 28.2 11 9.2 – 29.48 -0.09 40.1 40.5 – - – -
So what do people think the “tag-lines” are gonna look like for the local stations this next week??? My guesses are: KATU: “Arctic Express!”, KOIN: “Arctic Blast!”, KGW: “Heat Wave!”, and KPTV: “Dude, We Were Forecasting This Like A Week Ago!”
for KGW it will be business as usual with a slight mention of colder temps outside. Nothing will be said about the way they forecasted highs in the 40′s
I can see KGW’s headlines on Monday, “surprise arctic blast hits the area”
Great comedy! I always love listening to Dave on KATU (who was on KGW). The guy makes the weather forecast seem so elementary while scoring 50% during the winter. LOL!
Exactly guys, seems to me NWS is going with about an inch of snow on sunday?? but they are saying more might happen…
THE MORE IMPRESSIVELY COLD ARCTIC AIR MASS WILL ARRIVE ON SUNDAY WITH
A DEEPER UPPER LEVEL LOW DIGGING SOUTH OVER OREGON. MODELS SUGGEST A
BRIEF OVERWATER TRAJECTORY FOR THE COLD AIR AND SHOW THE UPPER LOW
PARTIALLY CUTTING OFF. GIVEN THESE FACTORS AND THE STRENGTH OF THE
UPPER LOW…ISOLATED TO SCATTERED SNOW SHOWERS ARE A POSSIBILITY ON
SUNDAY. AT THE MOMENT MOISTURE LOOKS TO BE THE LIMITING FACTOR WHICH
SHOULD KEEP ANY SNOW ACCUMULATIONS MINIMAL. MY ONE CONCERN ABOUT
THIS ASSUMPTION HOWEVER WOULD BE IF EXTRA FRONTAL DEVELOPMENT OCCURS
ALONG THE ARCTIC FRONT JUST OFFSHORE FUELED BY THE CONTRAST BETWEEN
THE VERY COLD AIR MASS AND THE WARMER MARINE AIR TO TE SOUTH. THE
DEGREE TO WHICH THE UPPER LOW STARTS TO CUT OFF COULD ALSO SUPPORT
THIS WITH THE ARCTIC FRONT STALLING 100 OR 150 MILES FURTHER NORTH
WHICH WOULD PUT IT OVER OUR CWA.
It says minimal snow. Where do you come up with an inch? It’s not going to snow otherwise Mark, Steve P or JacobBPA would post something.
this was their trend, very light accumulation, trace, light and now minimal
Anything is possible when a strong shortwave and arctic front move over a warmer ocean. Could spin up something near the central Oregon coast…
I think that’s what we are all hoping for!
I am pretty confident every one will see some snow ! Sunday morning so I am disagreeing with all forecasts
Or it could spin up something off of the central Washington coast! But, that is my bias coming in for locale!!
Mixing-mixer…-
Is that Thursday? That’s a pretty long way off…
yeaaa it is but i guess some hope maybe?
that’s true!
It seems like every time we have an arctic blast that as we get into the beginning of it suddenly it turns out to be colder, or lasts longer than previously expected… this will likely be the case again. Thursday-Friday it turns bitterly cold up north much colder than now into Alberta, eastern British Columbia, and the Northwest Territories(The origins of our arctic air masses). This is a very stable pattern we’ve evolved into with an Omega block that can last a long time and I just do not think it’s going to break down/pinch off as quick as models show. If we were to reload it will be a major blast for us next Friday into next weekend.
Wow just checking out this site: http://www.oregonphotos.com/Portland%20Cold.html, and it says that Portland Feb. 2, 3 1989 had highs of 15 and 18 and lows of 9 and 11! That’s a bit nippy…
Back during the Arctic Blast 2004 I had a high temp of 15.4F and low of 9F. East winds were 30-45mph. It was fun.
what were the 850mb temps then?
My deck is frozen right now. I can see stars, so getting clearer
snowstorm hour 162, a very big one as well!
Yes…in California
then the moisture moves onto here from south and north..suprisingly
My thoughts are that out to day 5-6 we have pretty good consistency, especially 500mb pattern. After day 6 seems models are confused still about the northern/southern stream and which one is dominant or do the two merge over southern Oregon? Do we re-load? I also don’t buy how the offshore block after day 5 looks. This is a stable pattern which I believe means future model runs will show the Gulf of Alaska high remaining strong probably longer than a week. As this comes to fruition then you’ll see a colder long term outlook.
Agree with you about the 5 day consistency but from there, Rob, you’re just speculating without a model….hope you’re dead on though.
wow, i jumped from 31 to 37f in one hour
ya I jumped up for a while too, when the N wind picked up a bit.
32.0 here…
-5.5c over Portland as of 03z at 850 mbs. I expect things to start freezing soild once it drops to near -6c. Tonight has got to be colder than last night.
http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?sat_850+1
This also means that the upper air at 5,000 feet is now cold enough for snow.
Too bad all the moisture is gone, for tonight anyways.
If the 850 mb temps keep falling at this rate. I would not be suprized if we stayed below 40f at PDX tomarrow.
Mark has PDX right at 40F tomorrow.
It could easily be 36-38 if the east winds pick up a bit earlier in the afternoon, IMO.
Well TTD-DLS turned offshore at 8 PM… Perhaps light east wind by midnight – 2 AM.
Hour 132
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer//gfs/00/gfs_ten120132_l.shtml
Brrrrrr continued offshore flow
Down to 33.6° already
Surface gradients
As of 8 PM|Current|Hourly Change
[Gorge]
PDX-DLS: +0.2mb | 0.4mb Decrease
TTD-DLS: -0.5mb | 0.6mb Increase – Offshore flow
[Fraser River Outflow]
BLI-YWL: -7.9mb | 0.4mb Increase
Is the arctic front moving into Washington?
I think the first boundary has yes. The true arctic air won’t be until late Saturday night/Sunday.
Wow…didn’t notice it was so clear already. The moon is beautiful, and the temperature is plummeting!
Tyler, what’s your temp now?
31.8
ALERT!!!
Possible low forming of washington coast at hour 90?!
maybe..
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/00/index_pcp_l_loop.shtml
Bellingham has warmed a few degrees, but the north wind is there and the humidity is dropping.