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.
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