Surface map for Saturday morning showing high pressure along the Carolina coast influencing our weather |
500mb (18,000′) level of the atmosphere. Zonal (west-to-east) flow indicates no major storm systems are in play across the continental U.S. |
In the map below, we are looking up even higher in the sky, about 34,000′ (or 250mb) or where the jet stream lives. We also see a fairly zonal flow here with no major ripples in the isobars, other than a moderate trough, or valley, off the U.S. east coast. In addition, the blue colors, which represent stronger wind and the location of the jet stream, is well to our north, roughly along the U.S./Canadian border. The jet stream separates warmer continental air from colder Arctic air, so that cold air is being bottled up over Canada.
250mb (34,000′) level of the atmosphere valid late Saturday. Zonal flow exists with the jet stream (blue colors) positioned along the U.S./Canadian border, pinning cold air north of the CONUS. |
Though the west coast of the U.S. has been pounded by a series of Pacific low pressure systems, the position of the jet stream well to our north will mean the brunt of these systems, as they move across the country, stays to our north, which is important as we look ahead to early next week.
One of these Pacific-origin systems will force the jet stream to begin to take a dip across the middle portion of the country by early in the week. This will allow a cold front to move into the region on Tuesday, bringing high chances of rain and possibly a few thunderstorms. This “dip” in the jet stream is reflected in the map below, valid late in the day Tuesday. You can see the valley that is formed by the black lines that extends roughly down the Mississippi River Valley.
Jet stream map (250mb) valid late Tuesday shows a pronounced trough (or valley) of low pressure over the middle of the country, trailing a cold front moving across the nation’s mid-section. |
The positive side of the front that moves through on Tuesday, besides some much needed rain, is that since it originated over the Pacific and not in Canada, the air behind it is not all that cold. So while we expect a cool down for mid-week, highs will likely still reach the 60s, which is well above normal for this time of year (normal high is in the mid 50s).
We’ll continue to monitor the front that arrives Tuesday and bring you any updates on rain and thunder chances. For now, severe weather chances look slim to non-existent as the front moves through. Click here for the complete MWN Forecast.
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Well, I still prefer this kind of weather than the summer heat. I tend to get lazy during those times and I just basically stay inside my air conditioned room when I couldn't stand the heat.