October 23, 2023
Monday Afternoon Update
The first frost of the season can end the growing season and kill sensitive plants. It may also produce frost for some locations and not others, depending on local topography. So you may be included and get a thick coating or nothing. It can be site-specific and helpful if you know how you compare to your surroundings.
A Frost Advisory has been issued by the National Weather Service for Tuesday morning. The map below includes much of Central Maryland, WEST of the Chesapeake Bay, and North Central Virginia. This region is covered by the Sterling, VA office.
Southern Pennsylvania region, which is covered by the State College, PA office, has posted an advisory to include Lancaster, York, and Adams counties, plus points north.
Below are the forecast maps for Tuesday morning AND the warm-up later this week. It is very common to have a quick snapback to warming after the first frost.
Note that colder spots are inland and valleys. Warmer spots that may not get frost or are the last to see it form are by water, in urban areas with more roads and buildings, and on hilltops (where warm air rises overnight).
UPDATE: This is the 3rd revision I had to make for this map… Because the different NWS offices do not post their alerts at the same time (and it gets even more confusing in winter)!
Most of Southern MD and Delmarva has even added.
Away from the water and city centers.
Light winds are expected. With a clear sky, it will allow for maximum cooling.
Temperatures can vary widely on clear mornings with light wind. So, in between these forecast locations, it can vary up to 5 degrees colder or warmer based on the topography.
This is right on target for most areas.
It is common at this time of year for wide temperature spreads from chilly mornings to mild afternoons.
With High Pressure, a Ridge will get established and pump in warmer winds all week.
It may feel like summer again for a few afternoons. As the leaves in central Maryland and Pennsylvania reach their peak color, temps will push into the upper 70s, and now I feel more confident there will be two days in the lower 80s.
A quiet weather week and shifting winds will allow the sun’s influence to be maximized. Top temps are expected to approach or surpass the 80s by the end of the week.
The crawling weather pattern may reach us with some showers on Sunday. That is still a question and not a promise.
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I am aware there are some spelling and grammar typos and occasional other glitches. I take responsibility for my mistakes and even the computer glitches I may miss. I have made a few public statements over the years, but if you are new here, you may have missed it: I have dyslexia and found out during my second year at Cornell University. It didn’t stop me from getting my meteorology degree and being the first to get the AMS CBM in the Baltimore/Washington region. One of my professors told me that I had made it that far without knowing and to not let it be a crutch going forward. That was Mark Wysocki, and he was absolutely correct! I do miss my mistakes in my own proofreading. The autocorrect spell check on my computer sometimes does an injustice to make it worse. I also can make mistakes in forecasting. No one is perfect at predicting the future. All of the maps and information are accurate. The ‘wordy’ stuff can get sticky. There has been no editor who can check my work when I need it and have it ready to send out in a newsworthy timeline. Barbara Werner is a member of the web team that helps me maintain this site. She has taken it upon herself to edit typos when she is available. That could be AFTER you read this. I accept this and perhaps proves what you read is really from me… It’s part of my charm.
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