Long Range Outlook - EPAWA Weather Consulting (2024)

OVERVIEW: The US drought monitor (photo toward the bottom of this outlook) maintained most of our region in abnormally dry conditions, while some areas were maintained in moderate drought stage with this week's update. Our August projections were adjusted this week for a slightly above average (+0.5" to +1.5") precipitation departure for the month as a whole, which would be quite the turnaround from the overall dry conditions experienced over the past 3 months, in large part due to the ENSO neutral background state and how that influences the late summer patterns locally. The presence of thunderstorms can skew monthly projections of rainfall on a hyper-local basis, and it is important to understand that the monthly projections in storm season are a composite average for the region as a whole, and based on synoptic events, not localized mesoscale-based activity. Our opening bid for the month of September as a whole was introduced this week for a near average (-0.5" to +0.5") precipitation departure.

Shorter term, a rigorous upper level trough will approach the region Friday, and slowly works its way eastward and through our region over the weekend. As a result of this expected propagation, scattered showers and thunderstorms are likely each day on a diurnally-driven basis, most notably during the afternoon and early evenings of each day when peak heating occurs. Due to the rather slow storm motions, severe weather will be limited and localized (wind) but the main threats will be from locally heavy rainfall with very high precipitable water content in the atmosphere, along with frequent lightning due to the higher instability in place. A cold front will approach Tuesday with scattered showers/thunderstorms, but the front may get hung up a bit Wednesday leading to additional showers/storms next Wednesday. The end of next week we will be monitoring a tropical wave currently near Eastern Cuba which could affect the Florida peninsula over the weekend. The eventuality of this system and its remnants are highly uncertain, and there is a non-zero chance to see some effects from this locally toward the end of next week...most likely with remnant rainfall. However there is low confidence in the track at this time, and the eventual track will not be known until at least early next week. Daily forecast videos on this website will continue to monitor progress in the week ahead.

The month of August we expect a slightly above average (+0.5" to +1.5") precipitation departure as a whole, with more recent modeling trends continuing to suggest more aggressive precipitation outlooks than we have seen in awhile. September projections were introduced this week for a near average (-0.5" to +0.5") precipitation departure for the month as a whole, using longer term climate models and seasonal trends with relation to the ENSO neutral background state.

Breakdown of precipitation departures from normal over the next several weeks:

August 3rd - August 9th: Slightly above average

August 10th - August 16th: Near to slightly above average

August 17th - August 23rd: Near to slightly above average

August 24th - August 30th: Near average

August 31st - September 6th: Near to slightly below average

September 7th - September 13th: Near average

Public/free available maps will be updated when a threat is imminent for significant weather on the weather alerts page throughout the year:http://epawaweather.com/weather-alerts/

Note: Any image below is clickable for larger viewing

OVERVIEW: We slightly adjusted August projections this week for a near to slightly above average (+0.0°F to +2.0°F) temperature departure for the month as a whole. A big part of that slight drop is tied to increased precipitation events throughout the month, and increased thunderstorm activity. While we could certainly use the rain across most of the region, this will also limit high temperatures somewhat at times. A very warm and muggy first week will be followed by a near to slightly BELOW average several days to begin week 2 of August, and near average for much of week 3. After that point, near to slightly above average temperatures are expected through mid-September as precipitation frequency abates somewhat. September projections were introduced this week for a near to slightly above average (0.0°F to +2.0°F) temperature departure for the month as a whole for the 2nd straight month.

The Madden-Julian Oscillation (MJO) is currently in the Circle of Death (COD) and a prolonged stretch in the Circle of Death is expected for much of August. This is very typical of a summer pattern where the overall flow is rather weak in the Pacific subtropical regions. Dynamical and statistical models have backed off the transition to a weak La Niña background state until the Autumn months, which means for the summer months an ENSO neutral pattern will likely maintain where we are currently. An ENSO neutral background state in the mid to late summer months typically features warmer than average temperatures, but also a wetter pattern overall. In August, precipitation departures look to increase to slightly above average levels after the past few months have been relatively dry. Our opening bid for September as a whole is to see a continuation of at least near to slightly above average temperatures. We will follow the tropics a bit more closely for local interests from this point forward, and the MJO is a key component to how active the Atlantic basin may be. Over the past few weeks, the MDR has been experiencing Saharan dust episodes that has muted tropical development...but this activity historically lessens its effect through August. This could mean a return to increased tropical activity, especially beyond mid-August. We will also be monitoring a tropical wave that may affect the Florida peninsula this weekend, but where it goes next week is still uncertain.

Average high temperatures are currently in the 84-87°F range from north to south across our coverage region, which is now on the slow decline after achieving annual climatological maximum temperatures in the weeks prior. Going forward, average highs and lows will be decreasing ever-so-slightly throughout August. Any above or below average stretches listed in the outlook will be relative to seasonal norms at that time, and it is important to note that cooler/warmer periods will be relative to the time of year we are talking about. For example, the neat to slightly below average temperatures listed between the 8th and 11th generally features highs on either side of 80° across the region, coming at a time when average highs are generally in the lower to middle 80s. Use the average highs/lows chart below that provides a point of reference for what average is for each corresponding date through mid-September.

The month of August projections were slightly adjusted this week to a near to slightly above average (+0.0°F to +2.0°F) temperature departure expectation, in large part due to the increased precipitation overall and frequency of those events. The month of September projections were introduced this week for another near to slightly above average (+0.0°F to +2.0°F) temperature departure using longer term climate guidance and global observation trends.

Note: Any image below is clickable for larger viewing`