Caribou, ME KCAR

Forecasting Week of 10/31/06 - 11/4/06

Introduction

For our fourth ePortfolio assignment, we were given the task of elaborating on our Weather Roundup, which is the recap of the week's weather events for the week we were Weather Briefer.  My week was October 30th through November 4th for Caribou, ME.  My original Weather Roundup page is linked following the Caribou climatology below, though I give a brief overview of the week's weather after that. 

In addition, we as a class were faced with many challenges during the second week of Caribou.  These challenges included precipitation, winds, and cloud cover.  I've elaborated a bit on each of these challenges on the following page, with a brief summary of how we handled forecasting for these situations.

And finally, the last page of this piece contains my reflections about this class and the certificate program, now that I've reached the end of it.  I've looked back through my previous class reflections and determined the area where I've grown the most, and tracked that growth through the four classes of the program.  In closing, I've shared my philosophy about weather and forecasting, which has formed based on my experiences while in the program.

And now, a little about Caribou and a summary of the synoptic weather pattern and weather events of my week as weather briefer. 

Climatology of Caribou ME

Caribou is located in the far northeast corner of the state of Maine.  The Caribou Municipal Airport (KCAR) sits at roughly the same elevation as the surrounding hills, 626 feet.  Though the Atlantic Ocean is 150 miles to the east, Caribou isn't much affected by its proximity, experiencing a mostly continental climate.  Continental polar (cP) and continental arctic (cA) fronts bring sub-zero temperatures and strong northwesterly winds in winter.  In autumn, which is when we were forecasting, the climate calls for mostly sunny, warm days and cool, chilly nights. In October, winds are predominately south-southwest at 3-5 knots, kicking up to 5-8 knot west-northwest winds with frontal passages.  In November, the winds change to predominately northwest-west at 5-8 knots, with 3-5 knot south-southwest/southeast winds ahead of the fronts.  The winds pick up with the seasonal transition due to increasing temperature gradients as the cold fronts come through, which also bring regular precipitation to the area, average normal amount being 0.10 inches.

Though a warm front and cold front from a low pressure system came through Caribou at the beginning of our forecast week, the system was moisture-starved and brought little precipitation to the area.  Most of the heavier precipitation with the system stayed south of Caribou.  The maximum sustained winds throughout the week remained high, though MOS predicted lighter winds.  The sunny, warm days and cool, chilly nights were greatly affected by the frontal system, WAA and CAA associated with the front, cloud cover and the winds.  All in all, this week was not anything like normal climatology.

The original Weather Roundup for my week as weather briefer is summarized below.  I've honed it down to the basic synoptic weather pattern and brief summary of events for each of the four days we forecast for.  Verification data can be seen in the table below for the week's high and low temperatures, maximum sustained winds, precipitation, and the climatological norms for these variables.  I've made an additional table with the MOS comparisons and my forecast to compare with the norms and actuals listed below.

Synoptic Weather Pattern and Summary of Events 

On Tuesday 10/31, Caribou was finally out from under the influence of the low pressure system that had passed to its northeast.  A high pressure ridge was in place with a westerly flow.  Winds were moderate and temperatures were cooler than climatological norms.  A warm front was approaching from the south which brought cloud cover to the area.  As the warm front passed, winds increased to 16 knots due to the increasing pressure gradient, and precipitation of 0.02 inches occurred at Caribou.  The meteogram for 06z-06z 10/31-11/1 shows the clouds clearing by 12Z 10/31 and a low of 32°F, then clouds moved back in by 18Z-19Z 10/31, winds calmed and a high of 41°F was reached, then the wind shifted to the south-southeast and precipitation occurred by 23Z 10/31.

This surface analysis valid 15Z 10/31 shows the low pressure system to the northeast of Caribou and the high pressure ridge extending from offshore across Caribou into eastern Canada.  Note the warm front approaching from the south.  Image from the Hydrometeorological Prediction Center (HPC).

On Wednesday 11/1, the warm front was located to the northeast and the cold front had passed to the east of Caribou.  Clearing allowed for solar heating, which brought the temperature up above climatological norms, but weak cold air advection arrived in the afternoon.  The strong pressure gradient still in place kept the winds at 17 knots.  The meteogram for 06z-06z 11/1-11/2 shows the south winds and cloudy conditions through 11Z, with rain at 06Z-07Z 11/1, then clearing skies by 12Z with a wind shift to the west, winds pick up, and temperatures begin to climb by 13Z 11/1.

This surface analysis valid 15Z 11/1 shows the location of the low pressure system and its warm and cold frontal boundaries.  Caribou is just west of the cold front and southwest of the warm front and occluded front triangle.  Image from the Hydrometeorological Prediction Center (HPC)

On Thursday 11/2, the frontal boundary remained just offshore, keeping a continued chance of showers (a trace of precipitation was recorded) and higher winds (12 knots) in the area.  The temperatures were starting to rebound closer to climatological norms.  The meteogram for 06z-06z 11/2-11/3 shows clouds moving in by 07Z-08Z where the low dipped to 29°F, winds picking back up from the southwest-south at 09Z, skies clearing again by 13Z with winds more westerly, the high climbs to 43°F at 19Z, and there is intermittent cloud cover at 23Z 11/2, 02Z 11/3, and 04Z 11/3.

This surface analysis valid 15Z 11/2 shows the warm/cold frontal boundary sitting offshore along the entire eastern coast.  Note the low pressure gradient now poised  to affect the Caribou area.  Image from the Hydrometeorological Prediction Center (HPC)

By Friday 11/3, the fronts had moved on and a high pressure ridge was building, bringing westerly flow.  Colder air moved in to bring the temperatures down once more.  Winds were again higher than normal at 17 knots.  The meteogram for 06z-06z 11/3-11/4 shows the clear skies and light southwest winds up to 11Z where the low dips to 22°F, then some high clouds move in briefly, skies mostly clear at 15Z-16Z, but clouds move back in and winds become northwesterly by 16Z, with the high temperature  of 37°F reached at 18Z 11/3.

This surface analysis valid 15Z 11/3 shows the low pressure system and its accompanying frontal boundaries moved considerably northeast of Caribou, and a high pressure ridge building over the area.  Image from the Hydrometeorological Prediction Center (HPC)

A table with the three MOS model forecasts in comparison to the norms and actuals points out where MOS busted on temperatures and winds.  I also included my forecast for each day.  From this table you can see the challenges that presented themselves during this week - the winds vs. MOS predictions, the precipitation amounts for Days 1 and 2, and the high and low temperatures for Days 1 and 2.

Challenges

Reflections