FC Discussion WED-FRI

Mean H pressure dominating the Continental US moves Eward ahead of approaching SW trough and assoc. PAC CF. At this time mean ZONAL flow still dominates EST 2/3CONT US. SFC L assoc. w/ Trop dist stauling off mean H pressure in the Bermuda south. This patteren leaves a W/WSW flow for daytime temp and assoc H temp accuracy being above norm. SFC winds expect to be light through next 30 hr period w/ weak press gradient. There is decent LL moisture available with no UL support at this time. L press. moves NNE and eventually ENE allowing H to move off of seaboard and approaching SW trough to accelerate. Immediate FC results suggest that an above normal high and low can be expected for next 24-36, although fluidity and rigidity of the approaching SW trough will come into play towards the end of the week(Thurs NT-FRI morn). Depending on the strength of the H as it moves into the Chesapeak Ba, and the rate of movement of the maritime L, CF could staul until Thurs NT, possibility for dissipation. Hold POPS for THURS to scattered in late am/aftn.

Webb

10/30/2007 KPWM

A ridge building in throughout the day tomorrow should result in clear skies tomorrow in Portland, ME, and anticyclonic flow to the north of the ridge will result in relatively dry air moving in fron the northwest into the Portland area. The air will have an easier time heating up since it's not the really moist air as is typical of this area if the flow is off the Atlantic, and as a result of this, I don't see any reason the high temperature tomorrow shouldn't reach the low 60's.

PWM Forecast Discussion

Calm winds, clear skies, & dry air Monday night will allow for good radiational cooling as temperatures will drop to near 32 F by Tuesday morning. High pressure will build into the region behind an exiting 500mb trough to the north during the day on Tuesday. Light westerly winds will provide some downslope warming as temperatures will reach the 50's F. Temperatures will remain above freezing on Tuesday night as clouds increase with a warm front.

Miller

KPWN - Tuesday, October 30th

High pressure moving in behind upper level trough which is now over open sea. Without much heating on Monday, and calm winds early Tuesday morning, we should see radiational cooling. Could see temperatures dip down below freezing. As the high approaches, pressure gradient should tighten during the early afternoon hours and with northwesterly flow at the surface, provide a little bit of compressional warming off of the White Mountains in New Hampshire. Daily maximum temperature should be much higher than Monday especially with decent daytime heating. Gradient will decrease toward 0Z and winds should quiet down and even shift to southerly winds which should keep Tuesday evening temperatures mild. Stable soundings and no significant moisture negate possibilities for precip.

Portland 10/30

I may not get to a computer again before the deadline for Tuesday's forecast so....
Another relatively boring weather day for the contest. High pressure moving offshore south of Portland should setup southwest flow and keep the weather fair while allowing the temperature to moderate from Monday.

Hot Water

When forecasting for coastal cities, sometimes it helps to know the temperature of the water ... especially if that's the direction the direction the wind is coming from.

Here's data from a buoy near Portland, Maine:

http://seaboard.ndbc.noaa.gov/station_page.php?station=44007

Maybe it will help!

Dann

Maximum Wind Speed Histogram for KPWM (2004-07)

Hey Gang:

Below is a histogram of the maximum windspeed of the day for the last 4 years over Portland, ME ASOS. Dr. Wagner made this and would like to share his climatology knowledge with y'all.

The long-term average is 15 knots, median is 14 knots. It looks like there are two main peaks. I think the first peak represents cold FROPA and daily onshore winds. The second peak is for nor'esters events.

~ Doc Ng


Maximum Wind Histogram for Portland, ME from 2004-2007 (courtsey of Dr. Wagner.
View Larger Image

WX Discussion for KPWM

Currently, a high pressure dominates the northeast bringing above temperatures to the Maine area until Monday. A cold front will pass through the KPWM sometime on Tuesday afternoon. This FROPA will usher in cloudy and rainy conditions for most of Tuesday and into parts of Wednesday. An upper-level cutoff low develops in the middle of the country by Wednesday bring unsettled weather for the Lower Mississippi and Ohio River Valley regions. As a result, a ridge will build in over the norrtheastern US for the end of this week. I expect normal temperatures over KPWM at the begining of the forecasting period and will increase steadly starting Thursday.

The GFS and Eta-WRF models are producing slightly different solutions for the upper-level low. The GFS has the low further east while, the Eta-WRF has it retrograding slightly west. This upper-low could effect how far the ridge is formed off the east coast as well as the weather in Denver for the latter part of this week.

Reverse Oregon Trail...Portland ME (KPWM)

Here are some essential information that will help all of us:


Identifier: KPWM
Elevation: 76 ft. / 23.2 m (surveyed)
From city: 2 miles W of PORTLAND, ME
Time zone: UTC -4 (UTC -5 during Standard Time)
Normal High 56 - 52°F
Normal Low 35 - 33°F
Normal Precipitation 0.15-0.16"



View Larger Map

Great Falls

Nothing exciting weatherwise for Great Falls on Tuesday. With upper level ridge building in things should be warm and dry. Brisk SE winds should help push high temperatures up 5-10 degress above normal. Things should become somewhat more interesting as the week progresses and the trough over the eastern Pacific moves in.

KGTF Discussion 10/08/2007

High pressure will be influencing the area tomorrow. Skies will be becoming more clear throughout the night, and as a result, the low should be somewhere near the low 40s just before sunrise. There will be a slight downslope influence on temperatures tomorrow, but slight warm air advection should allow temperatures tomorrow to climb higher than today. As a result of this and clear skies tomorrow, the high should be in the low to mid 70s. Don't go to low on the winds. Climatology suggests that this forecast site is historically windy. The max wind will probably be somewhere between 14-17kts tomorrow but even higher the next day.

KGTF 10/8

Large area SFC H situated over central N plains states. SSW flow becoming SW-WSW will bring a warming period for the short term. Gusts to 20+KT w/ tightened pressure gradient assoc. w/ SFC H. Weakened trough from weekend migrated NNW over N midwest leaving weak ridging behind it ahead of the next trough and deep L over PAC NW. Shallow CF becoming stationary and most likely weakening/dissipating WNW of forecast area, due to strengthening L offshore. FC temps should be higher than seasonal norms tomorrow(10/9) and becoming more seasonal midweek with oncoming baroclinic zone.

Great Falls Forecast Discussion

Large upper level trough currently digging into the Northwest United States. Strong southerly flow out ahead of approaching surface front in combination with high pressure over the central Rocky Mountains will lead to stiff southwest to south winds over the Rocky Mountain Front of northcentral Montana. Winds should continue through the forecast period and provide downslope heating and drying in the Great Falls area. Some high clouds will be in the area through the period due to the approaching trough but not enough to strongly effect the weather which will be dominated by the surface winds. Compressional heating from downslope off of the Belt Mountains will keep lows on Tuesday in the mid 40's and breezy conditions will persist into the afternoon, providing enough heating to take the temperature up into the 70's. Winds could gust as high as 30kt and a steady wind should stay between 15-20kt. No precipitation expected with strong drying at the surface and not much moisture available in the mid levels either. Some warm air advection will also keep the mid levels warm and keep the atmosphere stable.

Dann Cianca

KGFT Forecast Discussion

High pressure will dominate the region on Tuesday with above average temperatures. Low pressure & cooler temperatures will prevail late Wednesday through Saturday. High pressure will move back into the area on Sunday. Tuesday will be sunny & warm. A low pressure system will move into the area late in the day on Wednesday ushering in cooler temperatures, increasing cloudiness, & a slight chance of precipitation. 700mb temperatures will drop to 0 degrees Celsius by 0Z Thursday as a Pacific cold front passes through the district. This will translate to lows in the 30's F on Thursday morning. The better chances for precipitation will be confined to the mountains on Wednesday night. Clouds will decrease during the day Thursday, but high tempertures will reach only into the 50's to near 60 F. Clouds will increase again on Friday Night & Saturday with another slight chance of precipitation. Once again, the best chances for precipitation will be in the mountains. By Sunday, skies will clear with a ridge building into the area. Temperatures will remain near seasonal normals Thursday through Sunday.

Miller