The weekend and next week are shaping up to be very interesting times in respect to precipitation and water resources. First off, let’s discuss current trends and threats. I have a mix of both “dry” and “wet” trends and threats this week.
Northeast U.S. – Hurricane Sandy this weekend into next week (see below)
Pacific Northwest – The jet stream continues to focus Pacific storms on-shore over the PNW. Precipitation has been twice normal rates over the past few weeks. An additional 1-4 inches of rain can be expected in this region.
Portions of the Southwest and Southeast – I’m continuing my Trend Alert for well-below-normal rainfall for these areas through next week. Little, if any, rain is seen over the Southwest U.S. from southern California east into Texas. Only light amounts of rain are forecast for the southeast U.S.
Hurricane Sandy poses a significant risk to portions of the Northeast U.S. later this weekend and into next week. When a tropical system moves into the Northeast U.S., there is almost always the risk of serious inland flooding. Portions of this region have been fairly wet over the past 14 days (below) which would increase runoff rates.
Keep in mind that there are significant questions as to where Sandy will eventually go. Following is a image from a meteorological model next Monday. The feature that will impact where Sandy will go is the trough of low pressure swinging out of the Plains and into the Northeast. This is indicated by the solid red line. Sandy is indicated by the “L.” There are two options. The first is that this trough will “bump” Sandy towards the northeast and away from the U.S. The second is that Sandy will be “absorbed” by this trough and pull tropical moisture northwest.
The scenario where it would be pulled back towards the northwest is extremely rare. If it were to occur, this could become a historic rain event causing extreme amounts of rain and widespread flooding. Keep in mind that it is early in the game. Following are the latest track models. The American GFS model is on the left and the hurricane models on the right. For this type of system, I tend to lean slightly towards the GFS model. Again, the solution for this model is not good for the Northeast U.S.
disclaimer – Blue Water Outlook provides general information and insight regarding precipitation and water resources and not official warning or forecast information. Refer to official sources for watch, warning, and forecast information.